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  Subjects -> CHEMISTRY (Total: 762 journals)
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    - CHEMISTRY (527 journals)
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    - ORGANIC CHEMISTRY (40 journals)
    - PHYSICAL CHEMISTRY (64 journals)

INORGANIC CHEMISTRY (40 journals)

Acta Polymerica     Hybrid Journal   (4 followers)
Additives for Polymers     Full-text available via subscription   (17 followers)
Advances in Inorganic Chemistry     Full-text available via subscription   (4 followers)
Advances in Polymer Technology     Hybrid Journal   (9 followers)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (2 followers)
Bioinorganic Chemistry and Applications     Open Access   (4 followers)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal  
Current Methods in Inorganic Chemistry     Full-text available via subscription  
European Journal of Inorganic Chemistry     Hybrid Journal   (5 followers)
European Polymer Journal     Hybrid Journal   (41 followers)
Heterocyclic Communications     Full-text available via subscription   (2 followers)
High Performance Polymers     Hybrid Journal  
Indian Journal of Chemistry - Section A     Open Access   (4 followers)
Inorganic Chemistry     Full-text available via subscription   (17 followers)
Inorganic Chemistry Communications     Hybrid Journal   (7 followers)
Inorganic Chemistry Frontiers     Full-text available via subscription  
Inorganic Materials     Hybrid Journal   (2 followers)
Inorganic Materials: Applied Research     Hybrid Journal   (1 follower)
Inorganica Chimica Acta     Hybrid Journal   (4 followers)
Inorganics     Open Access  
International Journal of Inorganic Chemistry     Open Access   (1 follower)
ISRN Inorganic Chemistry     Open Access  
JBIC Journal of Biological Inorganic Chemistry     Hybrid Journal   (1 follower)
Journal of Inorganic and Organometallic Polymers and Materials     Partially Free   (6 followers)
Journal of Inorganic Biochemistry     Hybrid Journal   (3 followers)
Journal of Polymer Engineering     Full-text available via subscription   (7 followers)
Journal of Polymers and the Environment     Hybrid Journal   (3 followers)
Journal of Separation Science     Hybrid Journal   (6 followers)
Open Journal of Inorganic Chemistry     Open Access   (1 follower)
Plasmas and Polymers     Hybrid Journal  
Polymer Bulletin     Hybrid Journal   (6 followers)
Polymer Composites     Hybrid Journal   (7 followers)
Polyoxometalate Chemistry     Open Access  
Reviews in Inorganic Chemistry     Full-text available via subscription  
Russian Journal of Inorganic Chemistry     Hybrid Journal  
Studies in Inorganic Chemistry     Full-text available via subscription  
Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry     Hybrid Journal   (3 followers)
Topics in Inorganic and General Chemistry     Full-text available via subscription  
Zeitschrift für anorganische und allgemeine Chemie     Hybrid Journal   (1 follower)
Zeitschrift für Kristallographie - New Crystal Structures     Open Access  
Journal of Inorganic Biochemistry    [5 followers]  Follow    
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0162-0134
     Published by Elsevier Homepage  [2556 journals]   [SJR: 0.807]   [H-I: 79]
  • Cu(II)-catalyzed Oxidation of Dopamine in Aqueous Solutions: Mechanism and
           Kinetics
    • Abstract: Publication date: Available online 18 April 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): A. Ninh Pham , T. David Waite
      Spontaneous oxidation of dopamine (DA) and the resultant formation of free radical species within dopamine neurons of the substantia nigra (SN) is thought to bestow a considerable oxidative load upon these neurons and may contribute to their vulnerability to degeneration in Parkinson’s disease (PD). An understanding of DA oxidation under physiological conditions is thus critical to understanding the relatively selective vulnerability of these dopaminergic neurons in PD and may support the development of novel neuro-protective approaches for this disorder. In this study, the oxidation of dopamine (0.2 – 10μM) was investigated both in the absence and presence of copper (0.05 – 0.4μM), a redox active metal that is present at considerable concentrations in the SN, over a range of background chloride concentrations (0.01 – 0.7M), different oxygen concentrations and at physiological pH7.4. DA was observed to oxidize extremely slowly in the absence of copper and at moderate rates only in the presence of copper but without chloride. The oxidation of DA however was significantly enhanced in the presence of both copper and chloride with the rate of DA oxidation greatest at intermediate chloride concentrations (0.05 – 0.2M). The variability of the catalytic effect of Cu(II) on DA oxidation at different chloride concentrations can be explained and successfully modeled by appropriate consideration of the reaction of Cu(II) species with DA and the conversion of Cu(I) to Cu(II) through oxygenation. This model suggests that the speciation of Cu(II) and Cu(I) is critically important to the kinetics of DA oxidation and thus the vulnerability to degradation of dopaminergic neuron in the brain milieu.
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      PubDate: 2014-04-21T21:26:32Z
       
  • Effects of vanadium (III, IV, V)-chlorodipicolinate on glycolysis and
           antioxidant status in the liver of STZ-induced diabetic rats
    • Abstract: Publication date: July 2014
      Source:Journal of Inorganic Biochemistry, Volume 136
      Author(s): Mingxia Xie , Deliang Chen , Fang Zhang , Gail R. Willsky , Debbie C. Crans , Wenjun Ding
      Vanadium compounds exert various insulin-mimetic and anti-diabetic effects both in vitro and in vivo. Vanadium(III, IV, V)-chlorodipicolinate (Vdipic-Cl) compounds, including H[VIII(dipic-Cl)2]·5H2O (V3dipic-Cl), VIVO(dipic-Cl)(H2O)2 (V4dipic-Cl) and K[VVO2(dipic-Cl)] (V5dipic-Cl), were synthesized with the indicated oxidation states. The present study was conducted to investigate if chemical valence and anti-oxidation effects of vanadium compounds are involved in the anti-diabetic effects observed in streptozotocin (STZ)-induced diabetic rats treated with these vanadium compounds. V3dipic-Cl, V4dipic-Cl, V5dipic-Cl, inorganic vanadium salts vanadyl sulfate (VOSO4) or sodium metavanadate (NaVO3) were orally administered in drinking water (50μgV/ml) to STZ-induced diabetic rats for 28days. The results showed that Vdipic-Cl treatment significantly improved hyperglycemia and glucose intolerance, as well as increased hepatic glycogen synthesis in diabetic rats. The mRNA levels of key glycolytic enzymes in liver, phosphoenolpyruvate carboxykinase (PEPCK), glucokinase (GK), and L-pyruvate kinase (L-PK) altered in diabetic animals were significantly restored towards normal values by treatment with some of the vanadium compounds. Moreover, the diabetes elevated activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) in serum were significantly decreased after treatment with Vdipic-Cl complexes. Furthermore, treatment of diabetic rats with V4dipic-Cl and V5dipic-Cl compounds significantly reduced malondialdehyde (MDA) production and increased glutathione peroxidase (GSH-Px) and catalase (CAT) activities. These data suggest that vanadium compounds with the indicated chemical valence promote glycogen synthesis and recover suppressed glycolysis in the liver of diabetic rats due to their capacity to reduce oxidative stress by stimulating antioxidant enzymes.
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      PubDate: 2014-04-21T21:26:32Z
       
  • The type 1 copper site of pseudoazurin: Axial and rhombic
    • Abstract: Publication date: Available online 12 April 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Peter Gast , Freek G.J. Broeren , Silvia Sottini , Risa Aoki , Akiko Takashina , Takahide Yamaguchi , Takamitsu Kohzuma , Edgar J.J. Groenen
      We report on a high-frequency electron-paramagnetic-resonance study of the type 1 copper site of pseudoazurin. The spectra fully resolve the contribution of a nearly axial spectrum besides the rhombic spectrum, which unequivocally proves the existence of two conformations of the copper site. Pseudoazurins have been considered from Achromobacter cycloclastes including eight mutants and from Alcaligenes faecalis. The two conformations are virtually the same for all pseudoazurins, but the rhombic/axial population varies largely, between 91/9 and 33/67. These observations are discussed in relation to optical absorption spectra and X-ray diffraction structures. A similar observation for fern plastocyanin from Dryopteris crassirhizoma suggests that dual conformations of type 1 copper sites are more common.
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      PubDate: 2014-04-17T06:26:01Z
       
  • Selective hydrolysis of hen egg white lysozyme at Asp-X peptide bonds
           promoted by oxomolybdate
    • Abstract: Publication date: Available online 12 April 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Karen Stroobants , Phuong Hien Ho , Eva Moelants , Paul Proost , Tatjana N. Parac-Vogt
      The activity of oxomolybdate(VI) towards hen egg white lysozyme (HEWL) was examined under physiological and slightly acidic pH conditions. Purely hydrolytic cleavage of HEWL in the presence of 10 to 100mM of oxomolybdate(VI) after incubation at pH5.0 and 60°C for 2 to 7days was observed in SDS-PAGE experiments. Four cleavage sites, which all occurred at Asp-X sequences and included the Asp18-Asn19, Asp48-Gly49, Asp52-Trp53 and Asp101-Gly102 peptide bonds, were identified with Edman degradation. The molecular interaction between [MoO4]2- and HEWL was studied by circular dichroism (CD) and 1H-15 N heteronuclear single quantum correlation (HSQC) NMR spectroscopy. CD spectroscopy revealed a significant decrease in the α-helical content of HEWL upon addition of oxomolybdate, while 1H-15 N HSQC NMR spectroscopy identified the residues which were most affected upon interaction with [MoO4]2-. 95Mo NMR measurements, performed on oxomolybdate solutions containing HEWL, identified the monomeric [MoO4]2- form as active species in the hydrolytic reaction. The hydrolysis of the Asp-Gly model peptide in the presence of oxomolybdate(VI) was studied by 1H NMR, further supporting a hydrolytic mechanism where polarization of the carbonyl is followed by internal nucleophilic attack on the Asp residue.
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      PubDate: 2014-04-17T06:26:01Z
       
  • Spin equilibrium and O2-binding kinetics of Mycobacterium tuberculosis
           CYP51 with mutations in the histidine-threonine dyad
    • Abstract: Publication date: Available online 12 April 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Gareth K. Jennings , Anuja Modi , Justin E. Elenewski , Caroline M. Ritchie , Thuy Nguyen , Keith C. Ellis , John C. Hackett
      The acidic residues of the “acid-alcohol pair” in CYP51 enzymes are uniformly replaced with histidine. Herein, we adopt the Mycobacterium tuberculosis (mt) enzyme as a model system to investigate these residues roles in finely tuning the heme conformation, iron spin state, and formation and decay of the oxyferrous enzyme. Properties of the mtCYP51 and the T260A, T260V, and H259A mutants were interrogated using UV-Vis and resonance Raman spectroscopies. Evidence supports that these mutations induce comprehensive changes in the heme environment. The heme iron spin states are differentially sensitive to the binding of the substrate, dihydrolanosterol (DHL). DHL and clotrimazole perturb the local environments of the heme vinyl and propionate substituents. Molecular dynamics (MD) simulations of the DHL-enzyme complexes support that the observed perturbations are attributable to changes in the DHL binding mode. Furthermore, the rates of the oxyferrous formation were measured using stopped-flow methods. These studies demonstrate that both HT mutations and DHL modulate the rates of oxyferrous formation. Paradoxically, the binding rate to the H259A mutant-DHL complex was approximately four-fold that of mtCYP51, a phenomenon that is predicted to result from the creation of an additional diffusion channel from loss of the H259-E173 ion pair in the mutant. Oxyferrous enzyme auto-oxidation rates were relatively constant, with the exception of T260V-DHL complex. MD simulations lead us to speculate that this behavior may be attributed to distortion of the heme macrocycle by the substrate.
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      PubDate: 2014-04-17T06:26:01Z
       
  • Synthesis, characterization, crystal structures and biological activity of
           set of Cu(II) benzothiazole complexes: Artificial nucleases with cytotoxic
           activities
    • Abstract: Publication date: Available online 12 April 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Ramsey A. Steiner , David Foreman , Han X. Lin , Bruce K. Carney , Kristin M. Fox , Lynne Cassimeris , Joseph M. Tanski , Laurie A. Tyler
      A series of Cu(II) complexes with ligand frames based on quinoline derivatives appended with a benzothiazole substituent has been isolated. The complexes, Cu(Q(oBt))(NO3)2(H2O)∙CH3OH (1∙CH3OH), Cu(8OHQ(oBt))Cl2∙CH3OH (2∙CH3OH), Cu(8OQ(oBt))Cl(CH3OH)∙CH3OH (3∙CH3OH) and [Cu(8OH1/2Q(oBt))(CH3OH)(NO3)]2(NO3) (4) have been characterized by single crystal X-ray diffraction, IR and UV-visible spectroscopies, and elemental analysis. The ligand frame within the set of complexes differs in the substituent on the quinoline ring: complex 1 remains unsubstituted at this position while complexes 2 – 4 have a substituted –OH group. In complex 2, the bound phenol remains protonated while in 3 it is a phenolato group. Complex 4 contains two complexes within the unit cell and one NO3 - giving rise to an overall ‘half-protonation’. The interaction between complexes 1 – 3 with CT-DNA was investigated using fluorescence emission spectroscopy and revealed 2 and 3 strongly intercalate DNA with Kapp values of 1.47 x 107 M-1 and 3.09 x 107 M-1, respectively. The ability of complexes 1 – 3 to cleave SC-DNA was monitored using gel electrophoresis. Each complex exhibits potent, concentration dependent nuclease activity forming single and double-nicked DNA as low as 10 μM. The nuclease activity of complexes 1 – 3 is primarily dependent on 1O2 species while ·OH radicals play a secondary role in the cleavage by complexes 2 and 3. The cytotoxic effects of 1 – 3 were examined using HeLa cells and show cell death in the micromolar range. The distribution of cell cycle stages remains unchanged when complexes are present indicating DNA damage may be occurring throughout the cell cycle.
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      PubDate: 2014-04-17T06:26:01Z
       
  • Metal ions modulate thermal aggregation of beta-lactoglobulin: A join
           chemical and physical characterisation
    • Abstract: Publication date: Available online 13 April 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Giovanna Navarra , Anna Tinti , Michele Di Foggia , Maurizio Leone , Valeria Militello , Armida Torreggiani
      Molecular basis of the role played by Cu2+ and Zn2+ ions during the thermal aggregation processes of beta-lactoglobulin (BLG) were studied by using a joint application of different techniques. In particular, Raman spectroscopy was very useful in identifying the different effects caused by the two metals at molecular level (i.e. changes in His protonation state, disulfides bridge conformation, and micro-environment of aromatic residues), evidencing the primary importance of the protein charge distribution during the aggregation process. Both metal ions are able to act on this factor and favour the protein aggregation, but Zn2+ is able to alter the natural conformational state of BLG, causing a slight unfolding, whereas Cu2+ ions play a role only during the thermal treatment. Thus, Zn2+ ions favour the formation of bigger aggregates and branched fibril-like structures, whereas Cu2+ ions a greater number of cross-beta structures during thermal incubation, and, finally, fibrillar structures. The aggregation process occurs in two phases, as suggested by the measurements on the time evolution of the BLG aggregates: the first one is characterized by a partial unfolding of the protein and aggregates growth, forming oligomers and protofibrils, whereas the second one is characterized by further supramolecular assembly, leading to the formation of fibrils.
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      PubDate: 2014-04-17T06:26:01Z
       
  • A platinum(II) complex of liriodenine from traditional Chinese medicine
           (TCM): Cell cycle arrest, cell apoptosis induction and telomerase
           inhibition activity via G-quadruplex DNA stabilization
    • Abstract: Publication date: Available online 13 April 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Yu-Lan Li , Qi-Pin Qin , Yan-Cheng Liu , Zhen-Feng Chen , Hong Liang
      Liriodenine (L), an antitumor active ingredient from the traditional Chinese medicine (TCM), Zanthoxylum nitidum, afforded a platinum(II) complex (1) of L, cis-[PtCl2(L)(DMSO)], which previously reported for its in vitro antitumor activity and intercalative binding with DNA. In this study, complex 1 was further discussed for its antitumor mechanism and structure-activity relationship, comparing with L and cisplatin. Towards the most sensitive BEL-7404 human hepatoma cells, complex 1 significantly induced cell cycle arrest at both G2/M phase and S phase. It suggests that double helix DNA is not the simplex intracellular target for 1. On the other hand, the BEL-7404 cells incubated with 1 and stained by Hoechst 33258 and AO/EB showed typical cell apoptosis in dose-dependent manner. The BEL-7404 cells incubated with 1 and stained by JC-1 were also characteristic for cell apoptosis on the loss of mitochondrial membrane potential. Furthermore, the G-quadruplex DNA binding property of complex 1 was also investigated by spectroscopic analyses, fluorescent indicator displacement (FID) assay and fluorescence resonance energy transfer (FRET) assay. The results indicated that 1 stabilized the human telomeric G4-HTG21 DNA better than L. The telomerase inhibition ratio of 1 ((62.50±0.03)%), which was examined by telomerase Polymerase Chain Reaction – Enzyme-Linked Immunosorbent Assay (PCR-ELISA), was much higher than L ((21.77±0.01)%). It can be ascribed to the better G4-HTG21 DNA stabilization of 1 than L. The results suggested the nuclei, mitochondria and telomerase via G-quadruplex DNA stabilization all should be key targets for the antitumor mechanism of 1, in which the central platinum(II) played a key role.
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      PubDate: 2014-04-17T06:26:01Z
       
  • The cytotoxicity of the anticancer drug elesclomol is due to oxidative
           stress indirectly mediated through its complex with Cu(II)
    • Abstract: Publication date: Available online 16 April 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Brian B. Hasinoff , Arun A. Yadav , Daywin Patel , Xing Wu
      Elesclomol is an anticancer drug that is currently undergoing clinical trials. Elesclomol forms a strong 1:1 complex with Cu(II) and may exert its anticancer activity through the induction of oxidative stress and/or its ability to transport copper into the cell. A UV–vis spectrophotometric titration showed that Cu(I) also formed a 1:1 complex with elesclomol. Ascorbic acid, but not glutathione or NADH, potently reduced the Cu(II)-elesclomol complex to produce hydrogen peroxide. Even though hydrogen peroxide mediated reoxidation of the copper(I) produced by ascorbic acid reduction has the potential to lead to hydroxyl radical formation, electron paramagnetic resonance spin trapping experiments, either with or without added hydrogen peroxide, showed that the ascorbic acid-reduced Cu(II)-elesclomol complex could not directly generate damaging hydroxyl radicals. Both Cu(II)-elesclomol and elesclomol potently oxidized dichlorofluorescin in K562 cells. The highly specific copper chelators tetrathiomolybdate and triethylenetetramine were found to greatly reduce the cytotoxicity of both elesclomol and Cu(II)-elesclomol complex towards erythroleukemic K562 cells, consistent with a role for copper in the cytotoxicity of elesclomol. The superoxide dismutating activity of Cu(II)-elesclomol was much lower than that of Cu(II). Depletion of glutathione levels in K562 cells by treatment with buthionine sulfoximine sensitized cells to both elesclomol and Cu(II)-elesclomol. In conclusion, these results showed that elesclomol indirectly inhibited cancer cell growth through Cu(II)-mediated oxidative stress.
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      PubDate: 2014-04-17T06:26:01Z
       
  • Editorial Board
    • Abstract: Publication date: June 2014
      Source:Journal of Inorganic Biochemistry, Volume 135




      PubDate: 2014-04-17T06:26:01Z
       
  • Contents
    • Abstract: Publication date: June 2014
      Source:Journal of Inorganic Biochemistry, Volume 135




      PubDate: 2014-04-17T06:26:01Z
       
  • Lanthanide and transition metal complexes of bioactive coumarins:
           Molecular modeling and spectroscopic studies
    • Abstract: Publication date: June 2014
      Source:Journal of Inorganic Biochemistry, Volume 135
      Author(s): I. Georgieva , Tz. Mihaylov , N. Trendafilova
      The present paper summarizes theoretical and spectroscopic investigations on a series of active coumarins and their lanthanide and transition metal complexes with application in medicine and pharmacy. Molecular modeling as well as IR, Raman, NMR and electronic spectral simulations at different levels of theory were performed to obtain important molecular descriptors: total energy, formation energy, binding energy, stability, conformations, structural parameters, electron density distribution, molecular electrostatic potential, Fukui functions, atomic charges, and reactive indexes. The computations are performed both in gas phase and in solution with consideration of the solvent effect on the molecular structural and energetic parameters. The investigations have shown that the advanced computational methods are reliable for prediction of the metal–coumarin binding mode, electron density distribution, thermodynamic properties as well as the strength and nature of the metal–coumarin interaction (not experimentally accessible) and correctly interpret the experimental spectroscopic data. Known results from biological tests for cytotoxic, antimicrobial, anti-fungal, spasmolytic and anti-HIV activities on the studied metal complexes are reported and discussed.
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      PubDate: 2014-04-17T06:26:01Z
       
  • Dilution of dipolar interactions in a spin-labeled, multimeric
           metalloenzyme for DEER studies
    • Abstract: Publication date: July 2014
      Source:Journal of Inorganic Biochemistry, Volume 136
      Author(s): Mahesh Aitha , Timothy K. Richmond , Zhenxin Hu , Alyssa Hetrick , Raquel Reese , Althea Gunther , Robert McCarrick , Brian Bennett , Michael W. Crowder
      The metallo-β-lactamases (MβLs), which require one or two Zn(II) ions in their active sites for activity, hydrolyze the amide bond in β-lactam-containing antibiotics, and render the antibiotics inactive. All known MβLs contain a mobile element near their active sites, and these mobile elements have been implicated in the catalytic mechanisms of these enzymes. However little is known about the dynamics of these elements. In this study, we prepared a site-specific, double spin-labeled analog of homotetrameric MβL L1 with spin labels at positions 163 and 286 and analyzed the sample with DEER (double electron electron resonance) spectroscopy. Four unique distances were observed in the DEER distance distribution, and these distances were assigned to the desired intramolecular dipolar coupling (between spin labels at positions 163 and 286 in one subunit) and to intermolecular dipolar couplings. To rid the spin-labeled analog of L1 of the intermolecular couplings, spin-labeled L1 was “diluted” by unfolding/refolding the spin-labeled enzyme in the presence of excess wild-type L1. DEER spectra of the resulting, spin-diluted enzyme revealed a single distance corresponding to the desire intramolecular dipolar coupling.
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      PubDate: 2014-04-17T06:26:01Z
       
  • Anion inhibition studies of two α-carbonic anhydrases from Lotus
           japonicus, LjCAA1 and LjCAA2
    • Abstract: Publication date: Available online 8 April 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Daniela Vullo , Emmanouil Flemetakis , Andrea Scozzafava , Clemente Capasso , Claudiu T. Supuran
      The model organism for the investigation of symbiotic nitrogen fixation in legumes Lotus japonicus encodes two carbonic anhydrases (CAs, EC 4.2.1.1) belonging to the α-class, LjCAA1 and LjCAA2. Here we report the kinetic characterization and inhibition of these two CAs with inorganic and complex anions and other molecules interacting with zinc proteins, such as sulfamide, sulfamic acid, phenylboronic/arsonic acids. LjCAA1 showed a high catalytic activity for the CO2 hydration reaction, with a kcat of 7.4*105 s−1 and a kcat/Km of 9.6*107 M−1 s−1 and was inhibited in the low micromolar range by N,N-diethyldithiocarbamate, sulfamide, sulfamic acid, phenylboronic/arsonic acid (KIs of 4 – 62 μM). LjCAA2 showed a moderate catalytic activity for the physiologic reaction, with a kcat of 4.0*105 s−1 and a kcat/Km of 4.9*107 M−1 s−1. The same anions mentioned above for the inhibition of LjCAA1 showed the best activity against LjCAA2 (KIs of 7 – 29 μM). Nitrate and nitrite, anions involved in nitrogen fixation showed lower affinity for the two enzymes, with inhibition constants in the range of 3.7 – 7.0mM. Halides and sulfate also behaved in a distinct manner towards the two enzymes investigated here. As LjCAA1/2 participate in the pH regulation processes and CO2 metabolism within the nitrogen-fixing nodules of the plant, our studies may shed some light regarding these complex biochemical processes.
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      PubDate: 2014-04-12T11:13:37Z
       
  • Two water-soluble copper(II) complexes: Synthesis, characterization, DNA
           cleavage, Protein Binding Activities and in vitro anticancer activity
           studies
    • Abstract: Publication date: Available online 8 April 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Jing Lu , Qian Sun , Jun-Ling Li , Lin Jiang , Wen Gu , Xin Liu , Jin-Lei Tian , Shi-Ping Yan
      Two water-soluble ternary copper(II) complexes of [Cu(L)Cl](ClO4) (1) and [Cu(L)Br2] (2) (L=(2-((quinolin-8-ylimino)methyl)pyridine) were prepared and characterized by various physico-chemical techniques. Both 1 and 2 were structurally characterized by X-ray crystallography. The crystal structures show the presence of a distorted square-pyramidal CuN3Cl2 (1) or CuN3Br2 (2) geometry in which Schiff-base L act as a neutral tridentate ligand. Both complexes present intermolecular π-π stacking interactions between quinoline and pyridine rings. The interaction of two complexes with CT-DNA (calf thymus-DNA) and BSA (bovine serum albumin) was studied by means of various spectroscopy methods, which revealed that 1 and 2 could interact with CT-DNA through intercalation mode, and could quench the intrinsic fluorescence of BSA in a static quenching process. Furthermore, the competition experiment using Hoechst 33258 indicated that two complexes may bind to CT-DNA by minor groove. DNA cleavage experiments indicate that the complexes exhibit efficient DNA cleavage activities without any external agents, and hydroxyl radical (HO) and singlet oxygen (1O2) may serve as the major cleavage active species. Notably, the in vitro cytotoxicity of the complexes on three human tumor cells lines (HeLa, MCF-7, and A549) demonstrate that two compounds have broad-spectrum antitumor activity with a quite low IC50 ranges of 0.43-1.85 μM. Based on the cell cycle experiments, 1 and 2 could delay or inhibit cell cycle progression through the S phase.
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      PubDate: 2014-04-12T11:13:37Z
       
  • Antiparasitic activities of novel ruthenium/lapachol complexes
    • Abstract: Publication date: July 2014
      Source:Journal of Inorganic Biochemistry, Volume 136
      Author(s): Marília I.F. Barbosa , Rodrigo S. Corrêa , Katia Mara de Oliveira , Claudia Rodrigues , Javier Ellena , Otaciro R. Nascimento , Vinícius P.C. Rocha , Fabiana R. Nonato , Taís S. Macedo , José Maria Barbosa-Filho , Milena B.P. Soares , Alzir A. Batista
      The present study describes the synthesis, characterization, antileishmanial and antiplasmodial activities of novel diimine/(2,2′-bipyridine (bipy), 1,10-phenanthroline (phen), 4,4′-methylbipyridine (Me-bipy) and 4,4′-methoxybipyridine (MeO-bipy)/phosphine/ruthenium(II) complexes containing lapachol (Lap, 2-hydroxy-3-(3-33 methyl-2-buthenyl)-1,4-naphthoquinone) as bidentate ligand. The [Ru(Lap)(PPh3)2(bipy)]PF6 (1), [Ru(Lap)(PPh3)2(Me-bipy)]PF6 (2), [Ru(Lap)(PPh3)2(MeO-bipy)]PF6 (3) and[Ru(Lap)(PPh3)2(phen)]PF6 (4) complexes, PPh3 =triphenylphospine, were synthesized from the reactions of cis-[RuCl2(PPh3)2(X-bipy)] or cis-[RuCl2(PPh3)2(phen)], with lapachol. The [RuCl2(Lap)(dppb)] (5) [dppb=1,4-bis(diphenylphosphine)butane] was synthesized from the mer-[RuCl3(dppb)(H2O)] complex. The complexes were characterized by elemental analysis, molar conductivity, infrared and UV–vis spectroscopy, 31P{1H} and 1H NMR, and cyclic voltammetry. The Ru(III) complex, [RuCl2(Lap)(dppb)], was also characterized by the EPR technique. The structure of the complexes [Ru(Lap)(PPh3)2(bipy)]PF6 and [RuCl2(Lap)(dppb)] was elucidated by X-ray diffraction. The evaluation of the antiparasitic activities of the complexes against Leishmania amazonensis and Plasmodium falciparum demonstrated that lapachol–ruthenium complexes are more potent than the free lapachol. The [RuCl2(Lap)(dppb)] complex is the most potent and selective antiparasitic compound among the five new ruthenium complexes studied in this work, exhibiting an activity comparable to the reference drugs.
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      PubDate: 2014-04-12T11:13:37Z
       
  • Direct thermodynamic and kinetic measurements of Fe2+ and Zn2+ binding to
           human serum transferrin
    • Abstract: Publication date: July 2014
      Source:Journal of Inorganic Biochemistry, Volume 136
      Author(s): Tyson Terpstra , Justin McNally , Thi-Hong-Lien Han , Nguyet-Thanh Ha-Duong , Jean-Michel El-Hage-Chahine , Fadi Bou-Abdallah
      Human serum transferrin (hTf) is a single-chain bilobal glycoprotein that efficiently delivers iron to mammalian cells by endocytosis via the transferrin/transferrin receptor system. While extensive studies have been directed towards the study of ferric ion binding to hTf, ferrous ion interactions with the protein have never been firmly investigated owing to the rapid oxidation of FeII to FeIII and the difficulty in maintaining a fully anaerobic environment. Here, the binding of Fe2+ and Zn2+ ions to hTf has been studied under anaerobic and aerobic conditions, respectively, in the presence and absence of bicarbonate by means of isothermal titration calorimetry (ITC) and fluorescence spectroscopy. The ITC data indicate the presence of one class of strong binding sites with dissociation constants of 25.2nM for Fe2+ and 6.7nM for Zn2+ and maximum binding stoichiometries of 1 Zn2+ (or 1 Fe2+) per hTf molecule. With either metal, the binding interaction was achieved by both favorable enthalpy and entropy changes (ΔH0 approximately −12kJ/mol and ΔS0 ~106J/mol·K for Fe2+ and ΔH0 approximately −18kJ/mol and ΔS0 ~97J/mol·K for Zn2+). The large and positive entropy values are most likely due to the change in the hydration of the protein and the metal ions upon interaction. Rapid kinetics stopped-flow fluorescence spectroscopy revealed two different complexation mechanisms with different degrees of conformational changes upon metal ion binding. Our results are discussed in terms of a plausible scenario for iron dissociation from transferrin by which the highly stable Fe3+–hTf complex might be reduced to the more labile Fe2+ ion before iron is released to the cytosol.
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      PubDate: 2014-04-07T11:23:50Z
       
  • Enhanced anti-cancer efficacy to cancer cells by doxorubicin loaded
           
    • Abstract: Publication date: Available online 3 April 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Mei-Xia Zhao , Meng Zhao , Er-Zao Zeng , Yang Li , Jin-Ming Li , Qian Cao , Cai-Ping Tan , Liang-Nian Ji , Zong-Wan Mao
      The effectively targeted delivery of insoluble anticancer drugs to increase the intracellular drug concentration has become a focus in cancer therapy. In this system, two water-soluble amino acids-modified β-cyclodextrin (β-CD) platinum complexes were reported. They showed preferable binding ability to DNA and effective inhibition to cancer cells. And they could bind and unwind pBR322 DNA in a manner, which was similar to cisplatin. Besides, our platinum complexes could effectively deliver the anticancer drug doxorubicin (Dox) into cells and had higher cell inhibition ratio, but less toxicity on the normal cells, compared with cancer cells. In this combination system, Dox was encapsulated into the hydrophobic cavities of β-CD at the optimum molar ratio of 1:1, which were validated by UV-visible (UV–vis) absorption spectroscopy, fluorescence spectroscopy and MTT experiments. Moreover, the combination system had higher cell inhibition ratio than free Dox and amino acids-modified β-CD platinum complexes. And the results of high content screening (HCS) showed that Dox-loaded amino acids-modified β-CD platinum complexes could permeate the cell membrane and enter cells, suggesting the efficient transport of Dox across the membranes with the aid of the β-CD. We expect that the amino acids-modified β-CD platinum complexes will deliver antitumor drug Dox to enhance intracellular drug accumulation and such combination system showed great potential as antitumor drug.
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      PubDate: 2014-04-07T11:23:50Z
       
  • Effects of Mn-doping on the structure and biological properties of
           β-tricalcium phosphate
    • Abstract: Publication date: Available online 3 April 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): P.M.C. Torres , S.I. Vieira , A.R. Cerqueira , S. Pina , O.A.B. da Cruz Silva , J.C.C. Abrantes , J.M.F. Ferreira
      Doping calcium phosphates with trace elements that exist in bone tissues is beneficial in terms of cell-material interactions and in vivo performance of the bone grafts made thereof. Manganese (Mn) is an essential element for normal growth and metabolism of bone tissues, but studies reporting the effects of Mn-doping calcium phosphates are scarce. The present study investigated the influence of Mn-doping on the structure, morphology and biological properties of β-tricalcium phosphate [β-Ca3(PO4)2] (β-TCP). Mn-doped (MnTCP) powders, with Mn contents varying from 0–10mol. %), were obtained through an aqueous precipitation method followed by heat treatment at 800ºC. The successful incorporation of Mn into β-TCP structure was proved through quantitative X-ray diffraction (XRD) phase analysis coupled with structural Rietveld refinement. Increasing Mn concentrations led to decreasing trends of a- and c-axis lattice parameters, and Mn-doping also significantly affected the morphology of β-TCP powders. In vitro proliferation and differentiation assays of MC3T3-E1 osteoblastic-like cells, grown in the presence of the powders, revealed that the biological benefits of Mn-doped β-TCP are limited to lower Mn incorporation levels and potentially related to their surface microstructure. The Mn1-βTCP composition revealed the best set of bioactivity properties, potentially a good candidate for future applications of β-TCP materials in osteoregeneration.
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      PubDate: 2014-04-07T11:23:50Z
       
  • Thiosemicarbazone Cu(II) and Zn(II) complexes as potential anticancer
           agents: Syntheses, crystal structure, DNA cleavage, cytotoxicity and
           apoptosis induction activity
    • Abstract: Publication date: July 2014
      Source:Journal of Inorganic Biochemistry, Volume 136
      Author(s): Jia Shao , Zhong-Ying Ma , Ang Li , Ya-Hong Liu , Cheng-Zhi Xie , Zhao-Yan Qiang , Jing-Yuan Xu
      Four novel thiosemicarbazone metal complexes, [Cu(Am4M)(OAc)]·H2O (1), [Zn(HAm4M)Cl2] (2), [Zn2(Am4M)2Br2] (3) and [Zn2(Am4M)2(OAc)2]·2MeOH (4) [HAm4M=(Z)-2-(amino(pyridin-2-yl)methylene)-N-methylhydrazinecarbothioamide], have been synthesized and characterized by X-ray crystallography, elemental analysis, ESI-MS and IR. X-ray analysis revealed that complexes 1 and 2 are mononuclear, which possess residual coordination sites for Cu(II) ion in 1 and good leaving groups (Cl−) for Zn(II) ion in 2. Both 3 and 4 displayed dinuclear units, in which the metal atoms are doubly bridged by S atoms of two Am4M− ligands in 3 and by two acetate ions in bi- and mono-dentate forms, respectively, in 4. Their antiproliferative activities on human epithelial cervical cancer cell line (HeLa), human liver hepatocellular carcinoma cell line (HepG-2) and human gastric cancer cell line (SGC-7901) were screened. Inspiringly, IC50 value (11.2±0.9μM) of complex 1 against HepG-2 cells was nearly 0.5 fold of that against human hepatic cell lines LO2, showing a lower toxicity to human liver cells. Additionally, it displayed a stronger inhibition on the viability of HepG-2 cells than cisplatin (IC50 =25±3.1μM), suggesting complex 1 might be a potential high efficient antitumor agent. Furthermore, fluorescence microscopic observation and flow cytometric analysis revealed that complex 1 could significantly suppress HepG-2 cell viability and induce apoptosis. Several indexes, such as DNA cleavage, reactive oxygen species (ROS) generation, comet assay and cell cycle analysis indicated that the antitumor mechanism of complex 1 on HepG-2 cells might be via ROS-triggered apoptosis pathway.
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      PubDate: 2014-04-02T21:25:51Z
       
  • Promising antioxidant and anticancer (human breast cancer)
           oxidovanadium(IV) complex of chlorogenic acid. Synthesis, characterization
           and spectroscopic examination on the transport mechanism with bovine serum
           albumin
    • Abstract: Publication date: June 2014
      Source:Journal of Inorganic Biochemistry, Volume 135
      Author(s): Luciana G. Naso , María Valcarcel , Meritxell Roura-Ferrer , Danel Kortazar , Clarisa Salado , Luis Lezama , Teofilo Rojo , Ana C. González-Baró , Patricia A.M. Williams , Evelina G. Ferrer
      A new chlorogenate oxidovanadium complex (Na[VO(chlorog)(H2O)3].4H2O) was synthesized by using Schlenk methodology in the course of a reaction at inert atmosphere in which deprotonated chlorogenic acid ligand binds to oxidovanadium(IV) in a reaction experiment controlled via EPR technique and based in a species distribution diagram. The compound was characterized by FTIR, EPR, UV–visible and diffuse reflectance spectroscopies and thermogravimetric, differential thermal and elemental analyses. The ligand and the complex were tested for their antioxidant effects on DPPH (1,1-diphenyl-2-picrylhydrazyl radical), ABTS + (radical cation of 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt), O2 −, OH and ROO radicals and their cytotoxic activity on different cancer cell lines (SKBR3, T47D and MDAMB231) and primary human mammary epithelial cells. The complex behaved as good antioxidant agent with strongest inhibitory effects on O2 −, OH and ROO radicals and exhibited selective cytotoxicity against SKBR3 cancer cell line. Albumin interaction experiments denoted high affinity toward the complex and its calculated binding constant was indicative of a strong binding to the protein. Based on this study, it is hypothesized that Na[VO(chlorog)(H2O)3].4H2O would be a promising candidate for further evaluation as an antioxidant and anticancer agent.
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      PubDate: 2014-03-29T22:15:17Z
       
  • Influence of PPh3 moiety in the anticancer activity of new organometallic
           ruthenium complexes
    • Abstract: Publication date: July 2014
      Source:Journal of Inorganic Biochemistry, Volume 136
      Author(s): Rubén Sáez , Julia Lorenzo , Ma Jose Prieto , Mercè Font-Bardia , Teresa Calvet , Nuria Omeñaca , Marta Vilaseca , Virtudes Moreno
      The effect of the PPh3 group in the antitumor activity of some new organometallic ruthenium(II) complexes has been investigated. Several complexes of the type [Ru(II)(Cl)(PPh3)(Lig-N)], [Ru(II)(Cl)2(Lig-N)] (where Lig-N=pyridine derivate) and [Ru(II)(Cl)(PPh3)2], have been synthesized and characterized. A noticeable increment of the antitumor activity and cytotoxicity of the complexes due to the presence of PPh3 moiety has also been demonstrated, affording IC50 values of 5.2μM in HL-60 tumor cell lines. Atomic force microscopy, circular dichroism and electrophoresis experiments have proved that these complexes can bind DNA resulting in a distortion of both secondary and tertiary structures. Ethidium bromide displacement fluorescence spectroscopy studies and viscosity measurements support that the presence of PPh3 group induces intercalation interactions with DNA. Indeed, crystallographic analysis, suggest that intra-molecular π–π interactions could be involved in the intercalation within DNA base pairs. Furthermore, high performance liquid chromatography mass spectrometry (HPLC–MS) studies have confirmed a strong interaction between ruthenium complexes and proteins (ubiquitin and potato carboxypeptidase inhibitor — PCI) including slower kinetics due to the presence of PPh3 moiety, which could have an important role in detoxification mechanism and others. Finally, ion mobility mass spectrometry (IMMS) experiments have proved that there is no significant change in the gas phase structural conformation of the proteins owing to their bonding to ruthenium complexes.
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      PubDate: 2014-03-29T22:15:17Z
       
  • Synthesis, physico-chemical properties and biological analysis of newly
           obtained copper(II) complexes with pyrazole derivatives
    • Abstract: Publication date: June 2014
      Source:Journal of Inorganic Biochemistry, Volume 135
      Author(s): Magdalena Grazul , Emina Besic-Gyenge , Caroline Maake , Michal Ciolkowski , Malgorzata Czyz , Roland K.O. Sigel , Elzbieta Budzisz
      Three new copper(II) complexes containing two different pyrazole bound ligands (1, 2) have been synthesized and characterized by IR, LSI-MS (liquid secondary ion mass spectrometry) and elemental analysis. 1H NMR spectra of the organic ligands have been recorded. We describe the influence of these complexes on particular cancer cell lines and DNA structure by MTT-assay [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide], APA (acid phosphatase activity)-assay or CD-spectroscopy and agarose gel electrophoresis methods, together with their physico-chemical properties such as lipophilicity and stability in aqueous solution. The cytotoxic effect on HUVEC (endothelial cells) for the most active complex 4 has been also investigated. Moreover, the ability of these complexes to induce apoptosis in cancer cells has been assessed by using fluorescence microscopy. Our results indicate that dichloridobis{1-[amino(thioxo)methyl]-5-hydroxy-3-phenyl-1H-pyrazole-κN2}copper(II) is the most potent complex among the tested complexes.
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      PubDate: 2014-03-25T22:18:47Z
       
  • Nitrate as a probe of cytochrome c surfa Crystallographic identification
           of crucial “hot spots” for protein–protein recognition
    • Abstract: Publication date: June 2014
      Source:Journal of Inorganic Biochemistry, Volume 135
      Author(s): Matteo De March , Nicola Demitri , Rita De Zorzi , Angela Casini , Chiara Gabbiani , Annalisa Guerri , Luigi Messori , Silvano Geremia
      The electrostatic surface of cytochrome c and its changes with the iron oxidation state are involved in the docking and undocking processes of this protein to its biological partners in the mitochondrial respiratory pathway. To investigate the subtle mechanisms of formation of productive macromolecular complexes and of their breakage following the electron transfer process, the X-ray structures of horse heart ferri-cytochrome c (trigonal form) and ferro-cytochrome c (monoclinic form) were obtained using nitrate ions both as a crystallizing agent and an anionic probe for mapping the electrostatic surface changes. Both crystal forms contain three protein molecules in the asymmetric unit. In addition, a total of 21.5 and 18 crystallographically independent nitrate ions were identified for the trigonal and monoclinic forms, respectively. By matching all the six crystallographically independent protein molecules, 26 different anion–protein interaction sites were identified on the surfaces of cytochrome c, 10 of which were found in both forms, 8 present only in the oxidized and 8 only in the reduced form. The structural analysis of the electron transfer complexes, based on this new information, suggests a specific exit strategy for cytochrome c after formation of productive protein–protein complexes: a directional sliding mechanism for the electron shuttle on the surface of the redox partner is proposed to take place after the electron transfer process has occurred.
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      PubDate: 2014-03-25T22:18:47Z
       
  • Apo-neocarzinostatin: A protein carrier for Cu(II) glycocomplexes and
           Cu(II) into U937 and HT29 cell lines
    • Abstract: Publication date: June 2014
      Source:Journal of Inorganic Biochemistry, Volume 135
      Author(s): Ludivine Garcia , Susanna Franzoni , Francesca Mussi , Magali Aumont-Niçaise , Hélène Bertrand , Michel Desmadril , Giorgio Pelosi , Annamaria Buschini , Clotilde Policar
      In the field of pharmaceuticals there is an increasing need for new delivery systems to overcome the issues of solubility, penetration, toxicity and drug resistance. One of the possible strategies is to use biocarriers such as proteins to encourage the cell-penetration of drugs. In this paper, the use of the apo-protein neocarzinostatin (apo-NCS) as a carrier-protein for two Cu(II) glycocomplexes, previously characterized, and Cu(II) ions was investigated. Its interaction with the metallic compounds was analyzed using microcalorimetry. The dissociation constants were shown to be in the micromolar range. The Cu(II) glycocomplexes, in absence of apo-NCS, were found to be cytotoxic in the U937 and HT29 cell lines whereas the corresponding glycoligands showed no toxicity. The leukemic cell line (U937) seems to be more sensitive to glycocomplexes than the colon cancer cell line (HT29). Interestingly, apo-NCS was shown to increase systematically the antiproliferative activity by a factor of 2 and 3 for Cu(II) glycocomplexes and Cu(II) respectively. The antiproliferative activity detected was not related to proteasome inhibition. This result stresses the importance of new molecular tools for the delivery of Cu(II) to tumor cells using non-covalent association with carriers proteins.
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      PubDate: 2014-03-21T21:46:05Z
       
  • Controlled oxidation of aliphatic CH bonds in metallo-monooxygenases:
           Mechanistic insights derived from studies on deuterated and fluorinated
           hydrocarbons
    • Abstract: Publication date: May 2014
      Source:Journal of Inorganic Biochemistry, Volume 134
      Author(s): Yao-Sheng Chen , Wen-I Luo , Chung-Ling Yang , Yi-Jung Tu , Chun-Wei Chang , Chih-Hsiang Chiang , Chi-Yao Chang , Sunney I. Chan , Steve S.-F. Yu
      The control over the regio- and/or stereo-selective aliphatic CH oxidation by metalloenzymes is of great interest to scientists. Typically, these enzymes invoke host–guest chemistry to sequester the substrates within the protein pockets, exploiting sizes, shapes and specific interactions such as hydrogen-bonding, electrostatic forces and/or van der Waals interactions to control the substrate specificity, regio-specificity and stereo-selectivity. Over the years, we have developed a series of deuterated and fluorinated variants of these hydrocarbon substrates as probes to gain insights into the controlled CH oxidations of hydrocarbons facilitated by these enzymes. In this review, we illustrate the application of these designed probes in the study of three monooxygenases: (i) the particulate methane monooxygenase (pMMO) from Methylococcus capsulatus (Bath), which oxidizes straight-chain C1–C5 alkanes and alkenes to form their corresponding 2-alcohols and epoxides, respectively; (ii) the recombinant alkane hydroxylase (AlkB) from Pseudomonas putida GPo1, which oxidizes the primary CH bonds of C5–C12 linear alkanes; and (iii) the recombinant cytochrome P450 from Bacillus megaterium, which oxidizes C12–C20 fatty acids at the ω-1, ω-2 or ω-3 CH positions.
      Graphical abstract image

      PubDate: 2014-03-21T21:46:05Z
       
  • Contents
    • Abstract: Publication date: May 2014
      Source:Journal of Inorganic Biochemistry, Volume 134




      PubDate: 2014-03-21T21:46:05Z
       
  • Vanadium and cancer treatment: Antitumoral mechanisms of three
           oxidovanadium(IV) complexes on a human osteosarcoma cell line
    • Abstract: Publication date: May 2014
      Source:Journal of Inorganic Biochemistry, Volume 134
      Author(s): I.E. León , N. Butenko , A.L. Di Virgilio , C.I. Muglia , E.J. Baran , I. Cavaco , S.B. Etcheverry
      We report herein the antitumor actions of three oxidovanadium(IV) complexes on MG-63 human osteosarcoma cell line. The three complexes: VO(oda), VO(oda)bipy and VO(oda)phen (oda=oxodiacetate), caused a concentration dependent inhibition of cell viability. The antiproliferative action of VO(oda)phen could be observed in the whole range of concentrations (at 2.5μM), while VO(oda)bipy and VO(oda) showed a decrease of cell viability only at higher concentrations (at 50 and 75μM, respectively) (p<0.01). Moreover, VO(oda)phen caused a decrease of lysosomal and mitochondrial activities at 2.5μM, while VO(oda) and VO(oda)bipy affected neutral red uptake and mitochondrial metabolism at 50μM (p<0.01). On the other hand, no DNA damage studied by the Comet assay could be observed in MG-63 cells treated with VO(oda) at 2.5–10μM. Nevertheless, VO(oda)phen and VO(oda)bipy induced DNA damage at 2.5 and 10μM, respectively (p<0.01). The generation of reactive oxygen species increased at 10μM of VO(oda)phen and only at 100μM of VO(oda) and VO(oda)bipy (p<0.01). Besides, VO(oda)phen and VO(oda)bipy triggered apoptosis as determined by externalization of the phosphatidylserine. The determination of DNA cleavage by agarose gel electrophoresis showed that the ability of VO(oda)(bipy) is similar to that of VO(oda), while VO(oda)(phen) showed the highest nuclease activity in this series. Overall, our results showed a good relationship between the bioactivity of the complexes and their structures since VO(oda)phen presented the most potent antitumor action in human osteosarcoma cells followed by VO(oda)bipy and then by VO(oda) according to the number of intercalating heterocyclic moieties.
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      PubDate: 2014-03-21T21:46:05Z
       
  • Editorial Board
    • Abstract: Publication date: May 2014
      Source:Journal of Inorganic Biochemistry, Volume 134




      PubDate: 2014-03-21T21:46:05Z
       
  • Biological evaluation of bismuth non-steroidal anti-inflammatory drugs
           (BiNSAIDs): Stability, toxicity and uptake in HCT-8 colon cancer cells
    • Abstract: Publication date: June 2014
      Source:Journal of Inorganic Biochemistry, Volume 135
      Author(s): Emma L. Hawksworth , Philip C. Andrews , Wilford Lie , Barry Lai , Carolyn T. Dillon
      Recent studies showed that the metal-coordinated non-steroidal anti-inflammatory drug (NSAID), copper indomethacin, reduced aberrant crypt formation in the rodent colon cancer model, while also exhibiting gastrointestinal sparing properties. In the present study, the stability and biological activity of three BiNSAIDs of the general formula [Bi(L)3]n, where L=diflunisal (difl), mefenamate (mef) or tolfenamate (tolf) were examined. NMR spectroscopy of high concentrations of BiNSAIDs (24h in cell medium, 37°C) indicated that their structural stability and interactions with cell medium components were NSAID specific. Assessment of cell viability using the [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium]bromide (MTT) assay showed that the toxicity ranking of the BiNSAIDs paralleled those of the respective free NSAIDs: diflH<mefH<tolfH. While the IC50 values of the BiNSAIDs (ranging between 16 and 81μM) were lower than the free NSAIDs, it was apparent that the toxicity of the BiNSAIDs was due to the molar ratio of the three NSAID molecules contained in the BiNSAIDs, with the exception of [Bi(difl)3]. The highest cellular bismuth content was observed following treatment with [Bi(tolf)3]. Since NMR studies indicated that [Bi(tolf)3] was the most stable BiNSAID and that cellular uptake of bismuth correlated with structural stability it appears that bismuth uptake is assisted by the NSAID. Microprobe SR-XRF imaging showed that the intracellular fate of bismuth was independent of the specific BiNSAID treatment whereby all BiNSAID-treated cells showed bismuth accumulation in the cytoplasm within 24-h exposure. The size and location of the hot spots (0.3–5.8μm2), were consistent with cellular organelles such as lysosomes.
      Graphical abstract image

      PubDate: 2014-03-21T21:46:05Z
       
  • Disulfide bonds regulate binding of exogenous ligand to human cytoglobin
    • Abstract: Publication date: June 2014
      Source:Journal of Inorganic Biochemistry, Volume 135
      Author(s): Hirofumi Tsujino , Taku Yamashita , Azusa Nose , Kaori Kukino , Hitomi Sawai , Yoshitsugu Shiro , Tadayuki Uno
      Cytoglobin (Cgb) was discovered a decade ago and is a fourth member of the group of hexacoordinated globin-folded proteins. Although some crystal structures have been reported and several functions have been proposed for Cgb, its physiological role remains uncertain. In this study, we measured cyanide binding to the ferric state of the wild-type (WT) Cgb, and found that the binding consisted of multiple steps. These results indicated that Cgb may be comprised of several forms, and the presence of monomers, dimers, and tetramers was subsequently confirmed by SDS-PAGE. Remarkably, each species contained two distinguishable forms, and, in the monomer, analyses of alternative cysteine states suggested the presence of an intramolecular disulfide bond (monomer SS form) and a structure with unpaired thiol groups (monomer SH form). These confirmed that forms were separated by gel-exclusion chromatography, and that the cyanide binding of the separated fractions was again measured; they showed different affinities for cyanide, with the monomer fraction showing the highest affinity. In addition, the ferrous state in each fraction showed distinct carbon monoxide (CO)-binding properties, and the affinities for cyanide and CO suggested a linear correlation. Furthermore, we also prepared several variants involving the two cysteine residues. The C38S and C83S variants showed a binding affinity for cyanide similar to the value for the monomer SH form, and hence the fraction with the highest affinity for exogenous ligands was designated as a monomer SS form. We concluded that polymerization could be a mechanism that triggers the exertion of various physiological functions of this protein and that an appropriate disulfide bond between the two cysteine residues was critical for regulating the binding affinity of Cgb, which can act as a ROS scavenger, for exogenous ligands.
      Graphical abstract image

      PubDate: 2014-03-17T22:17:15Z
       
  • Re(I) tricarbonyl complex of 1,10-phenanthroline-5,6-dione: DNA binding,
           cytotoxicity, anti-inflammatory and anti-coagulant effects towards
           platelet activating factor
    • Abstract: Publication date: June 2014
      Source:Journal of Inorganic Biochemistry, Volume 135
      Author(s): Michael Kaplanis , George Stamatakis , Vasiliki D. Papakonstantinou , Maria Paravatou-Petsotas , Constantinos A. Demopoulos , Christiana A. Mitsopoulou
      The complex fac-[Re(CO)3(phendione)Cl] (1) (where phendione=1,10-phenanthroline-5,6-dione) has been synthesized and fully characterized by UV–visible, FTIR, and NMR techniques. The DNA binding properties of 1 are investigated by UV-spectrophotometric (melting curves), covalent binding assay, CV (cyclic voltammetry), circular dichroism (CD) and viscosity measurements. Experimental data indicate that 1 fits into the major groove without disrupting the helical structure of the B-DNA in contrast to the free phendione which intercalates within the base pairs of DNA. Upon irradiation, complex 1 promotes the cleavage of plasmid pBR322 DNA from supercoiled form I to nicked form II via a proton coupled electron transfer mechanism. This comes as a result of experimental data in anaerobic/aerobic conditions and in the presence of DMSO. The biological activities of 1 and its precursors [Re(CO)5Cl] and phendione are tested towards a series of cancerous cell lines as glioblastoma (T98G), prostate cancer (PC3) and breast cancer (MCF-7) as well as platelet activating factor (PAF)-aggregation. Moreover, all the aforementioned compounds are tested for their ability to modulate PAF-basic metabolic enzyme activities in preparations of rabbit leukolytes. The in vitro experiments indicate that phendione has a better antitumor effect than cisplatin whereas [Re(CO)5Cl] is a better PAF inhibitor than both the phendione ligand and 1. Moreover, for the first time it is indicated that [Re(CO)5Cl], with a IC50 of 17nM is comparable to the widely used PAF receptor antagonists, BN52021 and WEB2170 with IC50 of 30 and 20nM, respectively, whereas 1 affects PAF-catabolism.
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      PubDate: 2014-03-17T22:17:15Z
       
  • Use of Gold Nanoparticles as Crosslink Agent to Form Chitosan
           Nanocapsules: Study of the Direct Interaction in Aqueous Solutions
    • Abstract: Publication date: Available online 16 March 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): R. Prado-Gotor , G. López-Pérez , M.J. Martín , F. Cabrera-Escribano , A. Franconetti
      A systematic study of the interaction between free anionic gold nanoparticles and chitosan in solution is presented. A spectroscopic study of the interaction between 10nm gold nanoparticles and low molecular weight chitosan is reported as a function of the concentration and pH of the polymer in solution. Zeta potential measurements and TEM images indicate the effective aggregation of the nanoparticles in the presence of chitosan. At the same time, anionic gold nanoparticles act as crosslink agent to form chitosan nanocapsules with an average molecular size of 260nm. The changes of the surface plasmon band due to the adsorption of the polymer on the nanoparticles surface allow to use the citrate gold nanoparticles as sensor of the polymer for analytical purposes. The limit of detection for chitosan biopolymer is 69 nM. The optimum pH for the interaction between the biopolymer and the nanoparticles is found at a value of 6.4, obtained from spectrophotometric measurements and applying a deconvolution analysis of the experimental data. A simple model based on molecular surface electrostatic interactions is proposed to understand the pH dependence of the investigated system.
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      PubDate: 2014-03-17T22:17:15Z
       
  • Morphology-dependent bactericidal activities of Ag/CeO2 catalysts against
           Escherichia coli
    • Abstract: Publication date: Available online 11 March 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Lian Wang , Hong He , Yunbo Yu , Li Sun , Sijin Liu , Changbin Zhang , Lian He
      Silver-loaded CeO2 nanomaterials (Ag/CeO2) including Ag/CeO2 nanorods, nanocubes, nanoparticles were prepared with hydrothermal and impregnation methods. Catalytic inactivation of Escherichia coli with Ag/CeO2 catalysts through the formation of reactive oxygen species (ROS) was investigated. For comparison purposes, the bactericidal activities of CeO2 nanorods, nanocubes and nanoparticles were also studied. There was a 3-4 log order improvement in the inactivation of Escherichia coli with Ag/CeO2 catalysts compared with CeO2 catalysts. Temperature-programmed reduction of H2 showed that Ag/CeO2 catalysts had higher catalytic oxidation ability than CeO2 catalysts, which was the reason for that Ag/CeO2 catalysts exhibited stronger bactericidal activities than CeO2 catalysts. Further, the bactericidal activities of CeO2 and Ag/CeO2 depend on their shapes. Results of 5,5-dimethyl-1-pyrroline-N-oxide spin-trapping measurements by electron spin resonance and addition of catalase as a scavenger indicated the formation of •OH, •O2‾, and H2O2, which caused the obvious bactericidal activity of catalysts. The stronger chemical bond between Ag and CeO2 nanorods led to lower Ag+ elution concentrations. The toxicity of Ag+ eluted from the catalysts did not play an important role during the bactericidal process. Experimental results also indicated that Ag/CeO2 induced the production of intracellular ROS and disruption of the cell wall and cell membrane. A possible production mechanism of ROS and bactericidal mechanism of catalytic oxidation were proposed.
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      PubDate: 2014-03-13T20:35:37Z
       
  • Antibacterial Properties of Water-Soluble Gold(I) N-heterocyclic Carbene
           Complexes
    • Abstract: Publication date: Available online 11 March 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Gabriela A. Fernández , María S. Vela Gurovic , Nelda L. Olivera , Alicia B. Chopa , Gustavo F. Silbestri
      The antibacterial properties of water-soluble gold(I) complexes [1-Methyl-3-(3-sulfonatopropyl)imidazol-2-ylidene]gold(I) chloride (C1), [1-Mesityl-3-(3-sulfonatopropyl)imidazol-2-ylidene]gold(I) chloride (C2), [1-(2,6-Diisopropylphenyl)-3-(3-sulfonatopropyl)imidazol-2-ylidene]gold(I) chloride (C3) and [1,3-Bis(2,6-diisopropyl-4-sodiumsulfonatophenyl)imidazol-2-ylidene]gold(I) chloride (C4) and the respective ligands were assessed by agar diffusion and broth macrodilution methods against Gram-positives Staphylococcus aureus, Enterococcus faecalis and Micrococcus luteus; and the Gram-negative bacteria Yersinia ruckeri, Pseudomonas aeruginosa and Escherichia coli. Viability after treatments was determined by direct plate count. The bactericidal activity displayed by C1 and C3 was comparable to that of AgNO3.
      Graphical abstract image

      PubDate: 2014-03-13T20:35:37Z
       
  • Editorial Board
    • Abstract: Publication date: April 2014
      Source:Journal of Inorganic Biochemistry, Volume 133




      PubDate: 2014-03-13T20:35:37Z
       
  • Mechanism of reaction of chlorite with mammalian heme peroxidases
    • Abstract: Publication date: Available online 28 February 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Christa Jakopitsch , Katharina F. Pirker , Jörg Flemmig , Stefan Hofbauer , Denise Schlorke , Paul G. Furtmüller , Jürgen Arnhold , Christian Obinger
      This study demonstrates that heme peroxidases from different superfamilies react differently with chlorite. In contrast to plant peroxidases, like horseradish peroxidase (HRP), the mammalian counterparts myeloperoxidase (MPO) and lactoperoxidase (LPO) are rapidly and irreversibly inactivated by chlorite in the micromolar concentration range. Chlorite acts as efficient one-electron donor for Compound I and Compound II of MPO and LPO and reacts with the corresponding ferric resting states in a biphasic manner. The first (rapid) phase is shown to correspond to the formation of a MPO-chlorite high-spin complex, whereas during the second (slower) phase degradation of the prosthetic group was observed. Cyanide, chloride and hydrogen peroxide can block or delay heme bleaching. In contrast to HRP, the MPO/chlorite system does not mediate chlorination of target molecules. Irreversible inactivation is shown to include heme degradation, iron release and decrease in thermal stability. Differences between mammalian peroxidases and HRP are discussed with respect to differences in active site architecture and heme modification.
      Graphical abstract image

      PubDate: 2014-03-01T07:15:31Z
       
  • A cisplatin slow-release hydrogel drug delivery system based on a
           formulation of the macrocycle cucurbit[7]uril, gelatin and polyvinyl
           alcohol
    • Abstract: Publication date: Available online 18 February 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Rabbab Oun , Jane A. Plumb , Nial J. Wheate
      The anticancer drug cisplatin was encapsulated within the cucurbit[7]uril macrocycle to form the host-guest complex: cisplatin@CB[7]. This was then incorporated into gelatin and 0-4% w/v polyvinyl alcohol (PVA)-based hydrogels as slow release drug delivery vehicles. The hydrogels demonstrated predicable swelling and disintegration dependent on the PVA concentration. The hydrogel with the highest PVA content was slower to swell and release drug compared with lower concentrations of PVA. The effect of the hydrogel PVA concentration on in vitro cytotoxicity was examined using A2780/CP70 ovarian cancer cells. Over the 24h drug exposure time used, hydrogels containing 4% PVA showed a 20% decrease in viable cells compared to the control, whereas hydrogels containing 0% and 2% PVA induced an 80% and 45% inhibition of cell growth, respectively. There was no measurable difference in the in vitro cytotoxicity of free cisplatin and cisplatin@CB[7] containing hydrogels. Finally, the in vivo effectiveness of a 2%-PVA hydrogel implanted under the skin of nude mice bearing A2780/CP70 xenografts showed that low dose hydrogels containing cisplatin@CB[7] (30μg equivalent of drug) was just as effective as an intraperitoneal high dose administration of free cisplatin (150μg) at inhibiting tumour growth.
      Graphical abstract image

      PubDate: 2014-02-19T22:23:45Z
       
  • 2-Nitroimidazole-ruthenium polypyridyl complex as a new conjugate for
           cancer treatment and visualization
    • Abstract: Publication date: Available online 14 February 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Olga Mazuryk , Monika Maciuszek , Grażyna Stochel , Franck Suzenet , Małgorzata Brindell
      A novel long-lifetime highly luminescent ruthenium polypyridyl complex containing 2-nitroimidazole moiety [Ru(dip)2(bpy-2-nitroIm)]Cl2 (dip=4,7-diphenyl-1,10-phenanthroline, bpy-2-nitroIm=4-[3-(2-nitro-1H-imidazol-1-yl)propyl]-2,2'-bipyridine) has been designed cancer treatment and imaging. The luminescence properties of the synthesized compound strongly depend on the oxygen concentration. Under oxygen-free conditions quantum yield of luminescence and the average lifetime of emission were found to be 0.034 and 1.9μs, respectively, which is ca. three times higher in comparison to values obtained in air-equilibrated solution. The binding properties of the investigated ruthenium complex to human serum albumin have been studied and the apparent binding constant for the formation of the protein-ruthenium adduct was determined to be 1.1×105 M–1. The quantum yield and the average lifetime of emission are greatly enhanced upon binding of ruthenium compound to the protein. The DNA binding studies revealed two distinguished binding modes which lead to a decrease in luminescence intensity of ruthenium complex up to 60% for [DNA]/[Ru]<2, and enhancement of emission for [DNA]/[Ru]>80. Preliminary biological studies confirmed fast and efficient accumulation of the ruthenium complex inside cells. Furthermore, the ruthenium complex was found to be relatively cytotoxic with LD50 of 12 and 13μM for A549 and CT26 cell lines, respectively, under normoxic conditions. The retention and cellular uptake of ruthenium complex is enhanced under hypoxic conditions and its LD50 decreases to 8μM for A549 cell line.
      Graphical abstract image

      PubDate: 2014-02-15T22:21:28Z
       
  • Diverse in vitro and in vivo anti-inflammatory effects of
           trichlorido-gold(III) complexes with N6-benzyladenine derivatives
    • Abstract: Publication date: Available online 14 February 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Radka Křikavová , Jan Hošek , Pavel Suchý Jr. , Ján Vančo , Zdeněk Trávníček
      A series of gold(III) complexes involving differently substituted derivatives of a plant hormone N6-benzyladenine (HL1-5) is reported. The complexes have the general formula [Au(HL1-5)Cl3]∙nH2O (n=0 for 1, 3-5; and n=1 for 2), where N6-(2-fluorobenzyl)adenine (HL1), N6-(2-chlorobenzyl)adenine (HL2), N6-(3-chlorobenzyl)adenine (HL3), N6-(4-chlorobenzyl)adenine (HL4) and N6-(4-methylbenzyl)adenine (HL5) represent the N9-coordinated ligands. The results of thorough characterization (elemental and thermal analyses, FT-IR, Raman and NMR spectroscopy, ESI+mass spectrometry, conductivity measurements, DFT calculations) showed that the presented complexes 1-5 involve a central gold(III) atom coordinated in a square-planar geometry by the N9 atom of the purine moiety of HL1-5 and by three chlorido ligands. The complexes (1-5 ) were studied in vitro for cytotoxicity and anti-inflammatory activity on LPS-activated macrophages (THP-1 cell line), and in vivo for anti-inflammatory effects (1, 2, 5) using the carrageenan-induced hind paw oedema model on rats. Surprisingly, the results on the in vitro level revealed that the complexes show negligible cytotoxicity and anti-inflammatory activity, however, the activity on the in vivo level was found to be significant, fully comparable with the utilized drug Indomethacin, or even better as compared to a gold-containing metallodrug Auranofin.
      Graphical abstract image

      PubDate: 2014-02-15T22:21:28Z
       
  • A ruthenium(II) complex capable of inducing and stabilizing bcl-2
           G-quadruplex formation as a potential cancer inhibitor
    • Abstract: Publication date: May 2014
      Source:Journal of Inorganic Biochemistry, Volume 134
      Author(s): Jingnan Zhang , Qianqian Yu , Qian Li , Licong Yang , Lanmei Chen , Yanhui Zhou , Jie Liu
      Two ruthenium(II) complexes (Ru-complexes) were synthesized and characterized in this study. The selectivity and ability of the complexes to interact with bcl-2 DNA were investigated here. It turned out that [Ru(ip)3](ClO4)2·2H2O (complex 1, ip = 1H-iminazole [4,5-f][1,10] phenanthroline) could induce and stabilize the formations of G-quadruplexes more effectively than [Ru(pip)3](ClO4)2·2H2O (complex 2, pip = 2-phenylimidazo-[4,5-f][1,10]phenanthroline) did. Considering the important role of the Ru-complex ligand in inducing and stabilizing the formations of G-quadruplex in our previous studies, we speculate that the overlarge ligand of complex 2 may block its binding affinity for G-quadruplexes. Complex 1 also induced cell apoptosis in in vitro assays. In general, this study provided potentially important information for further development of the Ru-complexes as good inducers and stabilizers of bcl-2 G-quadruplex DNA for cancer treatment.
      Graphical abstract image

      PubDate: 2014-02-11T07:21:43Z
       
  • On the cytotoxic activity of Pd(II) complexes of N, N-disubstituted
           -N´-acyl thioureas
    • Abstract: Publication date: Available online 8 February 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Ana M. Plutín , Raúl Mocelo , Anislay Alvarez , Raúl Ramos , Eduardo E. Castellano , Marcia R. Cominetti , Angelica E. Graminha , Antonio G. Ferreira , Alzir A. Batista
      The rational design of anticancer drugs is one of the most promising strategies for increasing their cytotoxicity and for minimizing their toxicity. Manipulation of the structure of ligands or of complexes represents a strategy for which is possible to modify the potential mechanism of their action against the cancer cells. Here we present the cytotoxicity of some new palladium complexes and our intention is to show the importance of non-coordinated atoms of the ligands in the cytotoxicity of the complexes. New complexes of palladium (II), with general formulae [Pd(PPh3)2(L)]PF6 or [PdCl(PPh3)(L)], where L=N,N-disubstituted-N´-acyl thioureas, were synthesized and characterized by elemental analysis, molar conductivity, melting points, IR, NMR(1H, 13C and 31P{1H}) spectroscopy. The spectroscopic data are consistent with the complexes containing an O, S chelated ligand. The structures of complexes with N,N-dimethyl-N`-benzoylthiourea, N,N-diphenyl-N`-benzoylthiourea, N,N-diethyl-N´-furoylthiourea, and N,N-diphenyl-N`-furoylthiourea were determined by X-ray crystallography, confirming the coordination of the ligands with the metal through sulfur and oxygen atoms, forming distorted square-planar structures. The N,N-disubstituted-N´-acyl thioureas and their complexes were screened with respect to their antitumor cytotoxicity against DU-145 (human prostate cancer cells), MDA-MB-231 (human breast cancer cells) and their toxicity against the L929 cell line (health cell line from mouse).
      Graphical abstract image

      PubDate: 2014-02-11T07:21:43Z
       
  • Synthesis, characterization, thermal and DNA-binding properties of new
           zinc complexes with 2-hydroxyphenones
    • Abstract: Publication date: Available online 3 February 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Emina Mrkalić , Ariadne Zianna , George Psomas , Maria Gdaniec , Agnieszka Czapik , Evdoxia Coutouli-Argyropoulou , Maria Lalia-Kantouri
      The neutral mononuclear zinc complexes with 2-hydroxyphenones (ketoH) having the formula [Zn(keto)2(H2O)2] and [Zn(keto)2(enR)], where enR stands for a N,N'-donor heterocyclic ligand such as 2,2′-bipyridine (bipy), 1,10-phenanthroline (phen) or 2,2′-dipyridylamine (dpamH), have been synthesized and characterized by IR, UV and 1H NMR spectroscopies. The 2-hydroxyphenones are chelated to the metal ion through the phenolate and carbonyl oxygen atoms. The crystal structures of [bis(2-hydroxy-4-methoxy-benzophenone)(2,2’-bipyridine)zinc(II)] dimethanol solvate and [bis(2-hydroxy-benzophenone)(2,2’-bipyridine)zinc(II)] dimethanol solvate have been determined by X-ray crystallography. The thermal stability of the zinc complexes has been investigated by simultaneous TG/DTG-DTA technique. The ability of the complexes to bind to calf-thymus DNA (CT DNA) has been studied by UV-absorption and fluorescence emission spectroscopy as well as viscosity measurements. UV studies of the interaction of the complexes with DNA have shown that they can bind to CT DNA and the corresponding binding constants to DNA have been calculated and evaluated. The complexes most probably bind to CT DNA via intercalation as concluded by studying the viscosity of a DNA solution in the presence of the complexes. Competitive studies with ethidium bromide (EB) have shown that the reported complexes can displace the DNA-bound EB, suggesting strong competition with EB for the intercalation site.
      Graphical abstract image

      PubDate: 2014-02-06T07:21:06Z
       
  • Cytotoxicity of Cyclometalated Platinum Complexes Based on Tridentate NCN
           and CNN-coordinating ligands: Remarkable Coordination Dependence
    • Abstract: Publication date: Available online 3 February 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Dileep A.K. Vezzu , Qun Lu , Yan-Hua Chen , Shouquan Huo
      A series of cyclometalated platinum complexes with diverse coordination patterns and geometries were screened for their anticancer activity. It was discovered that the N^C^N-coordinated platinum complex based on 1,3-di(pyridyl)benzene displayed much higher cytotoxicity against human lung cancer cells NCI-H522, HCC827, and NCI-H1299, and human prostate cancer cell RV1 than cisplatin. In a sharp contrast, the C^N^N-coordinated platinum complex based on 6-phenyl-2,2’-bipyridine was ineffective on these cancer cells. This remarkable difference in cytotoxicity displayed by N^C^N- and C^N^N-coordinated platinum complexes was related to the trans effect of the carbon donor in the cyclometalated platinum complexes, which played a crucial role in facilitating the dissociation of the chloride ligand to create an active binding site. The DNA binding was studied for the N^C^N-coordinated platinum complex using electrophoresis and emission titration. The cellular uptake observed by fluorescent microscope showed the complex is largely concentrated in the cytoplasm. The possible pathways for the cell apoptosis was studied by western blot analysis and the activation of PARP via caspase 7 was observed.
      Graphical abstract image

      PubDate: 2014-02-06T07:21:06Z
       
  • Differential effects of aluminum on in vitro primary root growth, nutrient
           
    • Abstract: Publication date: Available online 3 February 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Jesús E. de A. Bojórquez-Quintal , Lucila A. Sánchez-Cach , Ángela Ku-González , Cesar de los Santos-Briones , María de Fátima Medina-Lara , Ileana Echevarría-Machado , José A. Muñoz-Sánchez , S.M. Teresa Hernández Sotomayor , Manuel Martínez Estévez
      C. arabica is a woody species that grows in acid soils, where aluminum is available and may affect growth and productivity. To determine the effect of aluminum on primary root growth of C. arabica cv. Typica, seedlings were exposed over 30days to different concentrations of AlCl3 (0, 100, 300 and 500μM) in vitro. The aluminum effect on primary root growth was dose-dependent: low aluminum concentrations (100 and 300μM) stimulated primary root growth (6.98±0.15 and 6.45±0.17cm, respectively) compared to the control (0μM; 5.24±0.17cm), while high concentrations (500μM) induced damage to the root tips and inhibition of primary root growth (2.96±0.28cm). Aluminum (100μM) also increased the K and Ca contents around 33% and 35% in the coffee roots. It is possible that aluminum toxicity resides in its association with cell nuclei in the meristematic region of the root. Additionally, after 30days of treatment with aluminum, two different effects could be observed on phospholipase C (PLC) activity. In shoots, aluminum concentrations≥300μM inhibited more than 50% of PLC activity. In contrast, in roots a contrasting behavior was determined: low (100μM) and toxic concentrations (500μM) increased the activity of PLC (100%). These results suggest the possible involvement of the phosphoinositide signal transduction pathway, with the phospholipase C enzyme participating in the beneficial and toxic effect of aluminum in plants.
      Graphical abstract image

      PubDate: 2014-02-06T07:21:06Z
       
  • Antitumor Pentamethylcyclopentadienyl Rhodium Complexes of Maltol and
           Allomaltol: Synthesis, Solution Speciation and Bioactivity
    • Abstract: Publication date: Available online 3 February 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Orsolya Dömötör , Sabine Aicher , Melanie Schmidlehner , Maria S. Novak , Alexander Roller , Michael A. Jakupec , Wolfgang Kandioller , Christian G. Hartinger , Bernhard K. Keppler , Éva A. Enyedy
      The reaction of the dimer [RhIII(pentamethylcyclopentadienyl)(μ-Cl)Cl]2 ([RhIII(Cp*)(μ-Cl)Cl]2) with the hydroxypyrone ligands maltol and allomaltol affords complexes of the general formula [RhIII(Cp*)(L)Cl] under standard and microwave conditions. The organometallic compounds were characterized by standard analytical methods and in the case of the allomaltol derivative in the solid state by single-crystal X-ray diffraction analysis. The complexes showed similar cytotoxicity profiles and were proved to be moderately active against various human cancer cell lines. The stoichiometry and stability of these complexes were determined in aqueous solution by pH-potentiometry, 1H NMR spectroscopy and UV-visible spectrophotometry. Speciation was studied in the presence and in the absence of chloride ions. Hydrolysis of [RhIII(Cp*)(H2O)3]2+ gave dimeric mixed hydroxido species [(RhIII(Cp*))2(μ–OH)3]+ and [(RhIII(Cp*))2(μ–OH)2Z2] (Z=H2O/Cl‒). Formation of the mononuclear complexes [RhIII(Cp*)(L)Z] of maltol and allomaltol with similar and moderate stability was found. These species predominate at physiological pH and decompose only partially at micromolar concentrations. In addition, hydrolysis of the aqua complex or the chlorido/hydroxido co-ligand exchange resulted in the formation of the mixed-hydroxido species [RhIII(Cp*)(L)(OH)] in the basic pH range. Replacement of the chlorido by an aqua ligand in the complex [RhIII(Cp*)(L)Cl] was monitored and with the help of the equilibrium constants the extent of aquation at various chloride concentrations of the extra- and intracellular milieu can be predicted. Complexation of these RhIII complexes was compared to analogous [RuII(η6-p-cymene)] species and higher conditional stabilities were found in the case of the RhIII compounds at pH7.4.
      Graphical abstract image

      PubDate: 2014-02-06T07:21:06Z
       
  • Synthesis, Spectroscopic and DFT Structural Characterization of Two Novel
           Ruthenium(III) Oxicam Complexes. In vivo Evaluation of anti-Inflammatory
           and Gastric Damaging Activities
    • Abstract: Publication date: Available online 24 January 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Gabriella Tamasi , Caterina Bernini , Gianfranco Corbini , Natalie F. Owens , Luigi Messori , Federica Scaletti , Lara Massai , Pietro Lo Giudice , Renzo Cini
      The reactions of ruthenium(III) chloride trihydrate with piroxicam (H2PIR) and tenoxicam (H2TEN), two widely used non-steroidal anti-inflammatory drugs, afforded [RuIIICl2(H2PIR)(HPIR)],·1, and [RuIIICl2(H2TEN)(HTEN)],·2. Both compounds were obtained as pure green solids through purification via flash column chromatography. Characterizations were accomplished through UV–vis and IR spectroscopy, potentiometry and HPLC. Quantum mechanics and density functional computational methods were applied to investigate their respective molecular structures. The experimental and computational results are in agreement with a pseudo-octahedral coordination where the two chlorido ligands are in trans positions (apical) and the two trans- N , O chelating oxicam ligands occupy the equatorial sites. Both compounds revealed an acceptable solubility and stability profile upon dissolution in a standard buffer at physiological pH. Nonetheless, addition of biologically occurring reducing agents caused spectral changes. The two complexes manifested a poor reactivity with the model proteins cytochrome c and lysozyme: no evidence for adduct formation was indeed obtained based on a standard ESI MS analysis; in contrast, some significant reactivity with serum albumin was proved spectrophotometrically. Remarkably, both study compounds revealed pronounced anti-edema effects in vivo suggesting that the pharmacological actions of the ligands are mostly retained; in addition, they were less irritating than piroxicam on the gastric mucosa when the coordination compounds and free oxicam were administered at the same overall molar concentration of the ligand. Overall, the present results point out that ruthenium coordination may represent an effective strategy to improve the pharmacological properties of oxicam drugs reducing their undesired side effects.
      Graphical abstract image

      PubDate: 2014-01-28T16:00:48Z
       
  • A Glance at the Reactivity of Osma(II)cycles [Os(C~N)x(bpy)3-x]m+ (x=0
           – 3) Covering a 1.8V Potential Range toward Peroxidase through Monte
           Carlo Simulations (–C~N=o-2-phenylpyridinato, bpy=2,2'-bipyridine)
    • Abstract: Publication date: Available online 22 January 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Ricardo Cerón-Camacho , Ronan Le Lagadec , Igor V. Kurnikov , Alexander D. Ryabov
      Three cyclometalated and one coordination compounds [Os(C~N) x (bpy)3-x ] m (x/m =0/2+ (4); 1/1+ (3); 2/1+ (2); 3/0 (1); –C~N=2-phenylpyridinato, bpy=2,2'-bipyridine) with drastically different reduction potentials have been used for analyzing the second-order rate constants for one-electron, metal-based osmium(II) to osmium(III) oxidation of the complexes by compound I (k 2) and compound II (k 3) of horseradish peroxidase. Previously unknown k 2 and k 3 have been determined by digital simulation of cyclic voltammograms measured in phosphate buffer of pH7.6 and 21±1°C. Osmium(II) species derived from osmium(III) complexes 1 and 2 were generated electrochemically in situ. Under the conditions used the reduction potentials for the OsIII/II feature equal −0.90, −0.095, 0.23 and 0.85V versus NHE (normal hydrogen electrode) for 1–4, respectively. The rate constants k 2 equal ~5×107, 6×108, 2×106 and 1×105 M-1 s-1 and the rate constants k 3 equal ~9×106, 4×107, 1×106 and 1×105 M-1 s-1 for complexes 1–4, respectively. Both rate constants k 2 and k 3 first increase with increasing the reaction driving force on going from 4 to 2 but then both decrease on going to complex 1 though the reaction driving force is the highest in this case. The system described has been explored theoretically using docking Monte Carlo simulations.
      Graphical abstract image

      PubDate: 2014-01-24T21:23:57Z
       
  • Nitric oxide photorelease from a trinuclear ruthenium nitrosyl complex and
           its in vitro cytotoxicity against melanoma cells
    • Abstract: Publication date: Available online 24 January 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Zumira A. Carneiro , Juliana C. Biazzotto , Anamaria.D.P. Alexiou , Sofia Nikolaou
      In vitro cytotoxicity study of the [Ru3O(CH3COO)6(4-pic)2(NO)]PF6 triruthenium nitrosyl cluster (compound 1, 4-pic=4-methylpyridine) against B16F10 melanoma cell line was evaluated in the presence and absence of visible light irradiation. The nitrosyl cluster 1 showed significant tumoricidal activity when irradiated at λ=532nm, reducing cell viability up to 90% at a concentration of 62,5μM. However, it is also observed cell death of 60 % in the dark which can be assigned to the NO release mediated by a redox reaction of the cluster in cell medium. This possibility was confirmed by amperometric detection of NO after addition of ascorbic acid to compound 1 in phosphate buffer. A control experiment was performed with the solvated cluster [Ru3O(CH3COO)6(4-pic)2(CH3OH)]PF6 (compound 2) and no significant lowering of cell viability was observed. These results suggest that the nitrosyl cluster acts as a pro-drug, delivering NO, which is the actual active species.
      Graphical abstract image

      PubDate: 2014-01-24T21:23:57Z
       
  • ZnII/pyridyloxime complexes as potential reactivators of OP-inhibited
           acetylcholinesterase: in vitro and docking simulation studies
    • Abstract: Publication date: Available online 7 January 2014
      Source:Journal of Inorganic Biochemistry
      Author(s): Konstantis F. Konidaris , Georgios A. Dalkas , Eugenia Katsoulakou , George Pairas , Catherine P. Raptopoulou , Fotini N. Lamari , Georgios A. Spyroulias , Evy Manessi-Zoupa
      In order to investigate the ability of metal complexes to act as reactivators of organophosphorus compounds (OP)-inhibited acetylcholinesterase (AChE), we have synthesized and crystallographically characterized three novel mononuclear ZnII complexes formulated as [ZnCl2{(4-py)CHNOH}2] (1), [ZnBr2{(4-py)CHNOH}2] (2) and [Zn(O2CMe)2{(4-py)CHNOH}2]∙2MeCN (3∙2MeCN), where (4-py)CHNOH is 4-pyridinealdoxime. Their reactivation potency was tested in vitro with a slight modification of Ellman’s method using Electric eel acetylcholinesterase and the insecticide paraoxon (diethyl 4-nitrophenyl phosphate) as inhibitor. The activity of the already reported complex [Zn2(O2CPh)2{(4-py)CHNOH}2]⋅2MeCN (4∙2MeCN) and of the clinically used drug obidoxime (1,1'-[oxybis(methylene)]bis{4-[(E)- (hydroxyimino)methyl]pyridinium} was also examined. The results of the in vitro experiments demonstrate moderate reactivation of the metal complexes compared to the drug obidoxime. On the other hand, it is clearly shown that the metal complex is the responsible molecular entity for the observed activity, as the reactivation efficacy of the organic ligand (4-pyridinealdoxime) is found to be inconsequential. Docking simulation studies were performed in the light of predicted complex-enzyme interactions using the paraoxon-inhibited enzyme along with the four ZnII complexes and obidoxime as a reference reactivator. The results showed that the three mononuclear metal complexes possess the required characteristics to be accommodated into the active site of AChE, while the entrance of the dinuclear ZnII compound is unsuccessful. An interesting outcome of docking simulations is the fact that the mononuclear compounds accommodate into the active site of AChE in a similar mode as obidoxime.
      Graphical abstract image

      PubDate: 2014-01-09T21:02:58Z
       
 
 
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