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Publisher: Springer-Verlag (Total: 2351 journals)

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Showing 1 - 200 of 2351 Journals sorted alphabetically
3D Printing in Medicine     Open Access   (Followers: 1)
3D Research     Hybrid Journal   (Followers: 21, SJR: 0.222, CiteScore: 1)
4OR: A Quarterly J. of Operations Research     Hybrid Journal   (Followers: 10, SJR: 0.825, CiteScore: 1)
AAPS J.     Hybrid Journal   (Followers: 22, SJR: 1.118, CiteScore: 4)
AAPS PharmSciTech     Hybrid Journal   (Followers: 7, SJR: 0.752, CiteScore: 3)
Abdominal Imaging     Hybrid Journal   (Followers: 15, SJR: 0.866, CiteScore: 2)
Abhandlungen aus dem Mathematischen Seminar der Universitat Hamburg     Hybrid Journal   (Followers: 4, SJR: 0.439, CiteScore: 0)
Academic Psychiatry     Full-text available via subscription   (Followers: 26, SJR: 0.53, CiteScore: 1)
Academic Questions     Hybrid Journal   (Followers: 8, SJR: 0.106, CiteScore: 0)
Accreditation and Quality Assurance: J. for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 27, SJR: 0.316, CiteScore: 1)
Acoustical Physics     Hybrid Journal   (Followers: 11, SJR: 0.359, CiteScore: 1)
Acoustics Australia     Hybrid Journal   (SJR: 0.232, CiteScore: 1)
Acta Analytica     Hybrid Journal   (Followers: 7, SJR: 0.367, CiteScore: 0)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 1, SJR: 0.675, CiteScore: 1)
Acta Biotheoretica     Hybrid Journal   (Followers: 4, SJR: 0.284, CiteScore: 1)
Acta Diabetologica     Hybrid Journal   (Followers: 18, SJR: 1.587, CiteScore: 3)
Acta Endoscopica     Hybrid Journal   (Followers: 1)
acta ethologica     Hybrid Journal   (Followers: 4, SJR: 0.769, CiteScore: 1)
Acta Geochimica     Hybrid Journal   (Followers: 7, SJR: 0.24, CiteScore: 1)
Acta Geodaetica et Geophysica     Hybrid Journal   (Followers: 2, SJR: 0.305, CiteScore: 1)
Acta Geophysica     Hybrid Journal   (Followers: 10, SJR: 0.312, CiteScore: 1)
Acta Geotechnica     Hybrid Journal   (Followers: 7, SJR: 1.588, CiteScore: 3)
Acta Informatica     Hybrid Journal   (Followers: 5, SJR: 0.517, CiteScore: 1)
Acta Mathematica     Hybrid Journal   (Followers: 12, SJR: 7.066, CiteScore: 3)
Acta Mathematica Hungarica     Hybrid Journal   (Followers: 2, SJR: 0.452, CiteScore: 1)
Acta Mathematica Sinica, English Series     Hybrid Journal   (Followers: 6, SJR: 0.379, CiteScore: 1)
Acta Mathematica Vietnamica     Hybrid Journal   (SJR: 0.27, CiteScore: 0)
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal   (SJR: 0.208, CiteScore: 0)
Acta Mechanica     Hybrid Journal   (Followers: 21, SJR: 1.04, CiteScore: 2)
Acta Mechanica Sinica     Hybrid Journal   (Followers: 5, SJR: 0.607, CiteScore: 2)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 7, SJR: 0.576, CiteScore: 2)
Acta Meteorologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.638, CiteScore: 1)
Acta Neurochirurgica     Hybrid Journal   (Followers: 6, SJR: 0.822, CiteScore: 2)
Acta Neurologica Belgica     Hybrid Journal   (Followers: 1, SJR: 0.376, CiteScore: 1)
Acta Neuropathologica     Hybrid Journal   (Followers: 4, SJR: 7.589, CiteScore: 12)
Acta Oceanologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.334, CiteScore: 1)
Acta Physiologiae Plantarum     Hybrid Journal   (Followers: 2, SJR: 0.574, CiteScore: 2)
Acta Politica     Hybrid Journal   (Followers: 15, SJR: 0.605, CiteScore: 1)
Activitas Nervosa Superior     Hybrid Journal   (SJR: 0.147, CiteScore: 0)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 8, SJR: 0.103, CiteScore: 0)
ADHD Attention Deficit and Hyperactivity Disorders     Hybrid Journal   (Followers: 23, SJR: 0.72, CiteScore: 2)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 9)
Administration and Policy in Mental Health and Mental Health Services Research     Partially Free   (Followers: 16, SJR: 1.005, CiteScore: 2)
Adsorption     Hybrid Journal   (Followers: 4, SJR: 0.703, CiteScore: 2)
Advances in Applied Clifford Algebras     Hybrid Journal   (Followers: 4, SJR: 0.698, CiteScore: 1)
Advances in Atmospheric Sciences     Hybrid Journal   (Followers: 37, SJR: 0.956, CiteScore: 2)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 19, SJR: 0.812, CiteScore: 1)
Advances in Contraception     Hybrid Journal   (Followers: 3)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 55, SJR: 1.09, CiteScore: 1)
Advances in Gerontology     Partially Free   (Followers: 8, SJR: 0.144, CiteScore: 0)
Advances in Health Sciences Education     Hybrid Journal   (Followers: 29, SJR: 1.64, CiteScore: 2)
Advances in Manufacturing     Hybrid Journal   (Followers: 4, SJR: 0.475, CiteScore: 2)
Advances in Polymer Science     Hybrid Journal   (Followers: 45, SJR: 1.04, CiteScore: 3)
Advances in Therapy     Hybrid Journal   (Followers: 5, SJR: 1.075, CiteScore: 3)
Aegean Review of the Law of the Sea and Maritime Law     Hybrid Journal   (Followers: 6)
Aequationes Mathematicae     Hybrid Journal   (Followers: 2, SJR: 0.517, CiteScore: 1)
Aerobiologia     Hybrid Journal   (Followers: 3, SJR: 0.673, CiteScore: 2)
Aesthetic Plastic Surgery     Hybrid Journal   (Followers: 9, SJR: 0.825, CiteScore: 1)
African Archaeological Review     Hybrid Journal   (Followers: 18, SJR: 0.862, CiteScore: 1)
Afrika Matematika     Hybrid Journal   (Followers: 1, SJR: 0.235, CiteScore: 0)
AGE     Hybrid Journal   (Followers: 7)
Ageing Intl.     Hybrid Journal   (Followers: 7, SJR: 0.39, CiteScore: 1)
Aggiornamenti CIO     Hybrid Journal   (Followers: 1)
Aging Clinical and Experimental Research     Hybrid Journal   (Followers: 3, SJR: 0.67, CiteScore: 2)
Agricultural Research     Hybrid Journal   (Followers: 6, SJR: 0.276, CiteScore: 1)
Agriculture and Human Values     Hybrid Journal   (Followers: 14, SJR: 1.173, CiteScore: 3)
Agroforestry Systems     Hybrid Journal   (Followers: 20, SJR: 0.663, CiteScore: 1)
Agronomy for Sustainable Development     Hybrid Journal   (Followers: 12, SJR: 1.864, CiteScore: 6)
AI & Society     Hybrid Journal   (Followers: 8, SJR: 0.227, CiteScore: 1)
AIDS and Behavior     Hybrid Journal   (Followers: 14, SJR: 1.792, CiteScore: 3)
Air Quality, Atmosphere & Health     Hybrid Journal   (Followers: 4, SJR: 0.862, CiteScore: 3)
Akupunktur & Aurikulomedizin     Full-text available via subscription   (Followers: 1)
Algebra and Logic     Hybrid Journal   (Followers: 6, SJR: 0.531, CiteScore: 0)
Algebra Universalis     Hybrid Journal   (Followers: 2, SJR: 0.583, CiteScore: 1)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1, SJR: 1.095, CiteScore: 1)
Algorithmica     Hybrid Journal   (Followers: 9, SJR: 0.56, CiteScore: 1)
Allergo J.     Full-text available via subscription   (Followers: 1, SJR: 0.234, CiteScore: 0)
Allergo J. Intl.     Hybrid Journal   (Followers: 2)
Alpine Botany     Hybrid Journal   (Followers: 5, SJR: 1.11, CiteScore: 3)
ALTEX : Alternatives to Animal Experimentation     Open Access   (Followers: 3)
AMBIO     Hybrid Journal   (Followers: 10, SJR: 1.569, CiteScore: 4)
American J. of Cardiovascular Drugs     Hybrid Journal   (Followers: 16, SJR: 0.951, CiteScore: 3)
American J. of Community Psychology     Hybrid Journal   (Followers: 29, SJR: 1.329, CiteScore: 2)
American J. of Criminal Justice     Hybrid Journal   (Followers: 8, SJR: 0.772, CiteScore: 1)
American J. of Cultural Sociology     Hybrid Journal   (Followers: 16, SJR: 0.46, CiteScore: 1)
American J. of Dance Therapy     Hybrid Journal   (Followers: 4, SJR: 0.181, CiteScore: 0)
American J. of Potato Research     Hybrid Journal   (Followers: 2, SJR: 0.611, CiteScore: 1)
American J. of Psychoanalysis     Hybrid Journal   (Followers: 21, SJR: 0.314, CiteScore: 0)
American Sociologist     Hybrid Journal   (Followers: 13, SJR: 0.35, CiteScore: 0)
Amino Acids     Hybrid Journal   (Followers: 8, SJR: 1.135, CiteScore: 3)
AMS Review     Partially Free   (Followers: 4)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 7, SJR: 0.211, CiteScore: 1)
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 5, SJR: 0.536, CiteScore: 1)
Analysis in Theory and Applications     Hybrid Journal   (Followers: 1)
Analysis of Verbal Behavior     Hybrid Journal   (Followers: 5)
Analytical and Bioanalytical Chemistry     Hybrid Journal   (Followers: 31, SJR: 0.978, CiteScore: 3)
Anatomical Science Intl.     Hybrid Journal   (Followers: 3, SJR: 0.367, CiteScore: 1)
Angewandte Schmerztherapie und Palliativmedizin     Hybrid Journal  
Angiogenesis     Hybrid Journal   (Followers: 3, SJR: 2.177, CiteScore: 5)
Animal Cognition     Hybrid Journal   (Followers: 19, SJR: 1.389, CiteScore: 3)
Annales françaises de médecine d'urgence     Hybrid Journal   (Followers: 1, SJR: 0.192, CiteScore: 0)
Annales Henri Poincaré     Hybrid Journal   (Followers: 3, SJR: 1.097, CiteScore: 2)
Annales mathématiques du Québec     Hybrid Journal   (Followers: 4, SJR: 0.438, CiteScore: 0)
Annali dell'Universita di Ferrara     Hybrid Journal   (SJR: 0.429, CiteScore: 0)
Annali di Matematica Pura ed Applicata     Hybrid Journal   (Followers: 1, SJR: 1.197, CiteScore: 1)
Annals of Biomedical Engineering     Hybrid Journal   (Followers: 18, SJR: 1.042, CiteScore: 3)
Annals of Combinatorics     Hybrid Journal   (Followers: 4, SJR: 0.932, CiteScore: 1)
Annals of Data Science     Hybrid Journal   (Followers: 12)
Annals of Dyslexia     Hybrid Journal   (Followers: 10, SJR: 0.85, CiteScore: 2)
Annals of Finance     Hybrid Journal   (Followers: 30, SJR: 0.579, CiteScore: 1)
Annals of Forest Science     Hybrid Journal   (Followers: 7, SJR: 0.986, CiteScore: 2)
Annals of Global Analysis and Geometry     Hybrid Journal   (Followers: 1, SJR: 1.228, CiteScore: 1)
Annals of Hematology     Hybrid Journal   (Followers: 15, SJR: 1.043, CiteScore: 2)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 13, SJR: 0.413, CiteScore: 1)
Annals of Microbiology     Hybrid Journal   (Followers: 11, SJR: 0.479, CiteScore: 2)
Annals of Nuclear Medicine     Hybrid Journal   (Followers: 4, SJR: 0.687, CiteScore: 2)
Annals of Operations Research     Hybrid Journal   (Followers: 10, SJR: 0.943, CiteScore: 2)
Annals of Ophthalmology     Hybrid Journal   (Followers: 12)
Annals of Regional Science     Hybrid Journal   (Followers: 7, SJR: 0.614, CiteScore: 1)
Annals of Software Engineering     Hybrid Journal   (Followers: 13)
Annals of Solid and Structural Mechanics     Hybrid Journal   (Followers: 9, SJR: 0.239, CiteScore: 1)
Annals of Surgical Oncology     Hybrid Journal   (Followers: 13, SJR: 1.986, CiteScore: 4)
Annals of Telecommunications     Hybrid Journal   (Followers: 9, SJR: 0.223, CiteScore: 1)
Annals of the Institute of Statistical Mathematics     Hybrid Journal   (Followers: 1, SJR: 1.495, CiteScore: 1)
Antonie van Leeuwenhoek     Hybrid Journal   (Followers: 5, SJR: 0.834, CiteScore: 2)
Apidologie     Hybrid Journal   (Followers: 4, SJR: 1.22, CiteScore: 3)
APOPTOSIS     Hybrid Journal   (Followers: 8, SJR: 1.424, CiteScore: 4)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2, SJR: 0.294, CiteScore: 1)
Applications of Mathematics     Hybrid Journal   (Followers: 2, SJR: 0.602, CiteScore: 1)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 43, SJR: 0.571, CiteScore: 2)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 17, SJR: 0.21, CiteScore: 1)
Applied Cancer Research     Open Access  
Applied Categorical Structures     Hybrid Journal   (Followers: 2, SJR: 0.49, CiteScore: 0)
Applied Composite Materials     Hybrid Journal   (Followers: 49, SJR: 0.58, CiteScore: 2)
Applied Entomology and Zoology     Partially Free   (Followers: 4, SJR: 0.422, CiteScore: 1)
Applied Geomatics     Hybrid Journal   (Followers: 3, SJR: 0.733, CiteScore: 3)
Applied Geophysics     Hybrid Journal   (Followers: 8, SJR: 0.488, CiteScore: 1)
Applied Intelligence     Hybrid Journal   (Followers: 12, SJR: 0.6, CiteScore: 2)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4, SJR: 0.319, CiteScore: 1)
Applied Mathematics & Optimization     Hybrid Journal   (Followers: 9, SJR: 0.886, CiteScore: 1)
Applied Mathematics - A J. of Chinese Universities     Hybrid Journal   (SJR: 0.17, CiteScore: 0)
Applied Mathematics and Mechanics     Hybrid Journal   (Followers: 5, SJR: 0.461, CiteScore: 1)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 65, SJR: 1.182, CiteScore: 4)
Applied Physics A     Hybrid Journal   (Followers: 10, SJR: 0.481, CiteScore: 2)
Applied Physics B: Lasers and Optics     Hybrid Journal   (Followers: 24, SJR: 0.74, CiteScore: 2)
Applied Psychophysiology and Biofeedback     Hybrid Journal   (Followers: 8, SJR: 0.519, CiteScore: 2)
Applied Research in Quality of Life     Hybrid Journal   (Followers: 12, SJR: 0.316, CiteScore: 1)
Applied Solar Energy     Hybrid Journal   (Followers: 18, SJR: 0.225, CiteScore: 0)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 5, SJR: 0.542, CiteScore: 1)
Aquaculture Intl.     Hybrid Journal   (Followers: 24, SJR: 0.591, CiteScore: 2)
Aquarium Sciences and Conservation     Hybrid Journal   (Followers: 2)
Aquatic Ecology     Hybrid Journal   (Followers: 34, SJR: 0.656, CiteScore: 2)
Aquatic Geochemistry     Hybrid Journal   (Followers: 4, SJR: 0.591, CiteScore: 1)
Aquatic Sciences     Hybrid Journal   (Followers: 13, SJR: 1.109, CiteScore: 3)
Arabian J. for Science and Engineering     Hybrid Journal   (Followers: 5, SJR: 0.303, CiteScore: 1)
Arabian J. of Geosciences     Hybrid Journal   (Followers: 2, SJR: 0.319, CiteScore: 1)
Archaeological and Anthropological Sciences     Hybrid Journal   (Followers: 21, SJR: 1.052, CiteScore: 2)
Archaeologies     Hybrid Journal   (Followers: 12, SJR: 0.224, CiteScore: 0)
Archiv der Mathematik     Hybrid Journal   (Followers: 1, SJR: 0.725, CiteScore: 1)
Archival Science     Hybrid Journal   (Followers: 62, SJR: 0.745, CiteScore: 2)
Archive for History of Exact Sciences     Hybrid Journal   (Followers: 7, SJR: 0.186, CiteScore: 1)
Archive for Mathematical Logic     Hybrid Journal   (Followers: 3, SJR: 0.909, CiteScore: 1)
Archive for Rational Mechanics and Analysis     Hybrid Journal   (SJR: 3.93, CiteScore: 3)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 5, SJR: 0.79, CiteScore: 2)
Archives and Museum Informatics     Hybrid Journal   (Followers: 143, SJR: 0.101, CiteScore: 0)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5, SJR: 1.41, CiteScore: 5)
Archives of Dermatological Research     Hybrid Journal   (Followers: 7, SJR: 1.006, CiteScore: 2)
Archives of Environmental Contamination and Toxicology     Hybrid Journal   (Followers: 14, SJR: 0.773, CiteScore: 2)
Archives of Gynecology and Obstetrics     Hybrid Journal   (Followers: 16, SJR: 0.956, CiteScore: 2)
Archives of Microbiology     Hybrid Journal   (Followers: 8, SJR: 0.644, CiteScore: 2)
Archives of Orthopaedic and Trauma Surgery     Hybrid Journal   (Followers: 8, SJR: 1.146, CiteScore: 2)
Archives of Osteoporosis     Hybrid Journal   (Followers: 2, SJR: 0.71, CiteScore: 2)
Archives of Sexual Behavior     Hybrid Journal   (Followers: 10, SJR: 1.493, CiteScore: 3)
Archives of Toxicology     Hybrid Journal   (Followers: 17, SJR: 1.541, CiteScore: 5)
Archives of Virology     Hybrid Journal   (Followers: 5, SJR: 0.973, CiteScore: 2)
Archives of Women's Mental Health     Hybrid Journal   (Followers: 14, SJR: 1.274, CiteScore: 3)
Archivio di Ortopedia e Reumatologia     Hybrid Journal  
Archivum Immunologiae et Therapiae Experimentalis     Hybrid Journal   (Followers: 2, SJR: 0.946, CiteScore: 3)
ArgoSpine News & J.     Hybrid Journal  
Argumentation     Hybrid Journal   (Followers: 6, SJR: 0.349, CiteScore: 1)
Arid Ecosystems     Hybrid Journal   (Followers: 2, SJR: 0.2, CiteScore: 0)
Arkiv för Matematik     Hybrid Journal   (Followers: 1, SJR: 0.766, CiteScore: 1)
Arnold Mathematical J.     Hybrid Journal   (Followers: 1, SJR: 0.355, CiteScore: 0)
Arthropod-Plant Interactions     Hybrid Journal   (Followers: 2, SJR: 0.839, CiteScore: 2)
Arthroskopie     Hybrid Journal   (Followers: 1, SJR: 0.131, CiteScore: 0)
Artificial Intelligence and Law     Hybrid Journal   (Followers: 11, SJR: 0.937, CiteScore: 2)
Artificial Intelligence Review     Hybrid Journal   (Followers: 16, SJR: 0.833, CiteScore: 4)
Artificial Life and Robotics     Hybrid Journal   (Followers: 9, SJR: 0.226, CiteScore: 0)
Asia Europe J.     Hybrid Journal   (Followers: 5, SJR: 0.504, CiteScore: 1)
Asia Pacific Education Review     Hybrid Journal   (Followers: 12, SJR: 0.479, CiteScore: 1)
Asia Pacific J. of Management     Hybrid Journal   (Followers: 16, SJR: 1.185, CiteScore: 2)
Asia-Pacific Education Researcher     Hybrid Journal   (Followers: 12, SJR: 0.353, CiteScore: 1)
Asia-Pacific Financial Markets     Hybrid Journal   (Followers: 2, SJR: 0.187, CiteScore: 0)
Asia-Pacific J. of Atmospheric Sciences     Hybrid Journal   (Followers: 19, SJR: 0.855, CiteScore: 1)
Asian Business & Management     Hybrid Journal   (Followers: 9, SJR: 0.378, CiteScore: 1)
Asian J. of Business Ethics     Hybrid Journal   (Followers: 9)
Asian J. of Criminology     Hybrid Journal   (Followers: 6, SJR: 0.543, CiteScore: 1)
AStA Advances in Statistical Analysis     Hybrid Journal   (Followers: 3, SJR: 0.548, CiteScore: 1)
AStA Wirtschafts- und Sozialstatistisches Archiv     Hybrid Journal   (Followers: 5, SJR: 0.183, CiteScore: 0)
ästhetische dermatologie & kosmetologie     Full-text available via subscription  

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Journal Cover
Amino Acids
Journal Prestige (SJR): 1.135
Citation Impact (citeScore): 3
Number of Followers: 8  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1438-2199 - ISSN (Online) 0939-4451
Published by Springer-Verlag Homepage  [2351 journals]
  • l -Glutamate nutrition and metabolism in swine
    • Authors: Yongqing Hou; Guoyao Wu
      Pages: 1497 - 1510
      Abstract: l-Glutamate (Glu) has traditionally not been considered as a nutrient needed in diets for humans and other animals (including swine) due to the unsubstantiated assumption that animals can synthesize sufficient amounts of Glu to meet their needs. The lack of knowledge about Glu nutrition has contributed to suboptimal efficiency of global livestock production. Over the past 25 years, there has been growing interest in Glu metabolism in the pig, which is an agriculturally important species and also a useful model for studying human biology. Because of analytical advances in its analysis, Glu is now known to be a highly abundant free amino acid in milk and intracellular fluid, a major constituent of food and tissue proteins, and a key regulator of gene expression, cell signaling, and anti-oxidative reactions. Emerging evidence shows that dietary supplementation with 2% Glu maintains gut health and prevents intestinal dysfunction in weanling piglets, while enhancing their growth performance and survival. In addition, the inclusion of 2% Glu is required for dietary arginine to maximize the growth performance and feed efficiency in growing pigs, whereas dietary supplementation with 2% Glu reduces the loss of skeletal muscle mass in endotoxin-challenged pigs. Furthermore, supplementing 2% Glu to a corn- and soybean-meal-based diet promotes milk production by lactating sows. Thus, an adequate amount of dietary Glu as a quantitatively major nutrient is necessary to support maximum growth, development, and production performance of swine. These results also have important implications for improving the nutrition and health of humans and other animals.
      PubDate: 2018-11-01
      DOI: 10.1007/s00726-018-2634-3
      Issue No: Vol. 50, No. 11 (2018)
  • Regulation of glucose and lipid metabolism by the pancreatic and
           extra-pancreatic actions of taurine
    • Authors: Rosane A. Ribeiro; Maria L. Bonfleur; Thiago M. Batista; Patricia C. Borck; Everardo M. Carneiro
      Pages: 1511 - 1524
      Abstract: The beneficial actions of l-taurine (Tau) against glucose intolerance, obesity, type 2 diabetes (T2D), and non-alcoholic fat liver disease (NAFLD) have been linked to its antioxidant and anti-inflammatory effects, which ameliorate tissue insulin sensitivity. Importantly, there are several lines of evidence that indicate a direct action of Tau on the endocrine pancreas to regulate the secretion and paracrine actions of insulin, glucagon, and somatostatin. Furthermore, Tau can also ameliorate glucose metabolism through the enhancement of insulin signaling. However, some of the benefits of Tau upon intermediary metabolism may manifest via considerable antagonism of the action of insulin. Therefore, this review discusses the mechanisms of action by which Tau may regulate endocrine pancreatic morphofunction, and glucose and lipid homeostasis.
      PubDate: 2018-11-01
      DOI: 10.1007/s00726-018-2650-3
      Issue No: Vol. 50, No. 11 (2018)
  • Supplementation with α-ketoglutarate to a low-protein diet enhances amino
           acid synthesis in tissues and improves protein metabolism in the skeletal
           muscle of growing pigs
    • Authors: Jiashun Chen; Wenxuan Su; Baoju Kang; Qian Jiang; Yurong Zhao; Chenxing Fu; Kang Yao
      Pages: 1525 - 1537
      Abstract: α-Ketoglutarate (AKG) is a crucial intermediate in the tricarboxylic acid (TCA) cycle and can be used for the production of ATP and amino acids in animal tissues. However, the effect of AKG on the expression patterns of genes involved in muscle protein metabolism is largely unknown, and the underlying mechanism remains to be elucidated. Therefore, we used young pigs to investigate the effects of a low crude protein (CP) diet and a low CP diet supplemented with AKG on protein accretion in their skeletal muscle. A total of 27 growing pigs with an initial body weight of 11.96 ± 0.18 kg were assigned randomly to one of the three diets: control (normal recommended 20% CP, NP), low CP (17% CP, LP), or low CP supplemented with 1% AKG (ALP). The pigs were fed their respective diets for 35 days. Free amino acid (AA) profile and hormone levels in the serum, and the expression of genes implicated in protein metabolism in skeletal muscle were examined. Results showed that compared with the control group or LP group, low-protein diets supplemented with AKG enhanced serum and intramuscular free AA concentrations, the mRNA abundances of AA transporters, and serum concentrations of insulin-like growth factor-1 (IGF-1), activated the mammalian target of rapamycin (mTOR) pathway, and decreased serum urea concentration and the mRNA levels for genes related to muscle protein degradation (P < 0.05). In conclusion, these results indicated that addition of AKG to a low-protein diet promotes amino acid synthesis in tissues and improves protein metabolism in skeletal muscle.
      PubDate: 2018-11-01
      DOI: 10.1007/s00726-018-2618-3
      Issue No: Vol. 50, No. 11 (2018)
  • Plasma profiling of amino acids distinguishes acute gout from asymptomatic
    • Authors: Ying Luo; Ling Wang; Xin-Ying Liu; Xiaolong Chen; Ya-Xiang Song; Xin-Hua Li; Cizong Jiang; Ai Peng; Jun-Yan Liu
      Pages: 1539 - 1548
      Abstract: Gout and hyperuricemia are highly prevalent metabolic diseases caused by high level of uric acid. Amino acids (AAs) involve in various biochemical processes including the biosynthesis of uric acid. However, the role of AAs in discriminating gout from hyperuricemia remains unknown. Here, we report that the plasma AAs profile can distinguish acute gout (AG) from asymptomatic hyperuricemia (AHU). We established an LC–MS/MS-based method to measure the plasma AAs without derivatization for the AG and AHU patients, and healthy controls. We found that the plasma profiling of AAs separated the AG patients from AHU patients and controls visually in both principal component analysis and orthogonal partial least-squares discriminant analysis (OPLS-DA) models. In addition, l-isoleucine, l-lysine, and l-alanine were suggested as the key mediators to distinguish the AG patients from AHU and control groups based on the S-plot analysis and variable importance in the projection values in the OPLS-DA models, volcano plot, and the receiver operating characteristic curves. In addition, the saturation of monosodium urate in the AA solutions at physiologically mimic status supported the changes in plasma AAs facilitating the precipitation of monosodium urate. This study suggests that l-isoleucine, l-lysine, and l-alanine could be the potential markers to distinguish the AG from AHU when the patients have similar blood levels of uric acid, providing new strategies for the prevention, treatment, and management of acute gout.
      PubDate: 2018-11-01
      DOI: 10.1007/s00726-018-2627-2
      Issue No: Vol. 50, No. 11 (2018)
  • Enantioselective permeations of amino acids through l -proline-modified
           gold nanochannel membrane: an experimental and theoretical study
    • Authors: Lu Huang; Yanxia Li; Qi Lin; Benyong Lou; Yiting Chen
      Pages: 1549 - 1556
      Abstract: l-Proline-modified gold nanochannel membrane (l-Pro-GNM) was prepared and applied for the enantioselective permeations of amino acid enantiomers including tyrosine (Tyr), tryptophan (Trp) and phenylalanine (Phe). Experimental results show that l-Pro-GNM has enantioselectivities for Tyr and Phe enantiomers. Furthermore, the chiral recognition mechanism was studied by density functional theory (DFT) and reduced density gradient (RDG). DFT computational results illustrate that the fundamental chiral recognition system contains two chiral selectors and one selectand, which can be used to evaluate the enantioselective efficiencies of other chiral compounds and the enantioselective ability of other potential amino acid-modified GNM. Finally, graphs obtained by RDG using Multiwfn show helpful visual interactions between the chiral selector and selectand. Results indicate that the electrostatic interaction and hydrogen bonding are responsible for the binding of the chiral selector and selectand, and the larger binding energy shows larger van der Waals interactions.
      PubDate: 2018-11-01
      DOI: 10.1007/s00726-018-2629-0
      Issue No: Vol. 50, No. 11 (2018)
  • Membrane affinity and fluorescent labelling: comparative study of
           monolayer interaction, cellular uptake and cytotoxicity profile of
           carboxyfluorescein-conjugated cationic peptides
    • Authors: Éva Kiss; Gergő Gyulai; Edit Pári; Kata Horváti; Szilvia Bősze
      Pages: 1557 - 1571
      Abstract: Fluorescent labelling is a common approach to reveal the molecular details of cellular uptake, internalisation, transport, distribution processes in biological systems. The conjugation with a fluorescent moiety might affect relevant physico-chemical and in vitro transport properties of the bioactive component. A representative set of seven cationic peptides—including cell-penetrating peptides as well as antimicrobial peptides and synthetic derivatives—was selected for our comparative study. Membrane affinity of the peptides and their 5(6)-carboxyfluorescein (Cf) derivatives was determined quantitatively and compared applying Langmuir monolayer of zwitterionic (DPPC) and negatively charged (DPPC + DPPG) lipids as cell membrane models. The interaction with neutral lipid layer is mainly governed by the overall hydrophobicity of the molecule which is remarkably increased by Cf-conjugation for the most hydrophobic Magainin, Melittin and Transportan. A significantly enhanced membrane affinity was detected in negatively charged lipid model monolayer for all of the peptides since the combination of electrostatic and hydrophobic interaction is active in that case. The Cf-conjugation improved the penetration ability of Penetratin and Dhvar4 suggesting that both the highly charged character (Z/n) and the increased hydrophobicity by Cf-conjugation present important contribution to membrane interaction. This effect might also responsible for the observed high in vitro internalisation rate of Penetratin and Dhvar4, while according to in vitro studies they did not cause damage of cell membrane. From the experiments with the given seven cationic peptides, it can be concluded that the Cf-conjugation alters the degree of membrane interaction of such peptides which are moderately hydrophobic and highly charged.
      PubDate: 2018-11-01
      DOI: 10.1007/s00726-018-2630-7
      Issue No: Vol. 50, No. 11 (2018)
  • Design of antimicrobial peptides from a cuttlefish database
    • Authors: Baptiste Houyvet; Bruno Zanuttini; Erwan Corre; Gildas Le Corguillé; Joël Henry; Céline Zatylny-Gaudin
      Pages: 1573 - 1582
      Abstract: No antimicrobial peptide has been identified in cephalopods to date. Annotation of transcriptomes or genomes using basic local alignment Search Tool failed to yield any from sequence identities. Therefore, we searched for antimicrobial sequences in the cuttlefish (Sepia officinalis) database by in silico analysis of a transcriptomic database. Using an original approach based on the analysis of cysteine-free antimicrobial peptides selected from our Antimicrobial Peptide Database (APD3), the online prediction tool of the Collection of Anti-Microbial Peptides (CAMPR3), and a homemade software program, we identified potential antibacterial sequences. Nine peptides less than 25 amino acids long were synthesized. The hydrophobic content of all nine of them ranged from 30 to 70%, and they could form alpha-helices. Three peptides possessed similarities with piscidins, one with BMAP-27, and five were totally new. Their antibacterial activity was evaluated on eight bacteria including the aquatic pathogens Vibrio alginolyticus, Aeromonas salmonicida, or human pathogens such as Salmonella typhimurium, Listeria monocytogenes, or Staphylococcus aureus. Despite the prediction of an antimicrobial potential for eight of the peptides, only two—GR21 and KT19—inhibited more than one bacterial strain with minimal inhibitory concentrations below 25 µM. Some sequences like VA20 and FK19 were hemolytic, while GR21 induced less than 10% of hemolysis on human blood cells at a concentration of 200 µM. GR21 was the only peptide derived from a precursor with a signal peptide, suggesting a real role in cuttlefish immune defense.
      PubDate: 2018-11-01
      DOI: 10.1007/s00726-018-2633-4
      Issue No: Vol. 50, No. 11 (2018)
  • Allosteric inhibition site of transglutaminase 2 is unveiled in the N
    • Authors: Nayeon Kim; Joon Hee Kang; Won-Kyu Lee; Seul-Gi Kim; Jae-Seon Lee; Seon-Hyeong Lee; Jong Bae Park; Kyung-Hee Kim; Young-Dae Gong; Kwang Yeon Hwang; Soo-Youl Kim
      Pages: 1583 - 1594
      Abstract: Previously we have demonstrated transglutaminase 2 (TGase 2) inhibition abrogated renal cell carcinoma (RCC) using GK921 (3-(phenylethynyl)-2-(2-(pyridin-2-yl)ethoxy)pyrido[3,2-b]pyrazine), although the mechanism of TGase 2 inhibition remains unsolved. Recently, we found that the increase of TGase 2 expression is required for p53 depletion in RCC by transporting the TGase 2 (1–139 a.a)–p53 complex to the autophagosome, through TGase 2 (472–687 a.a) binding p62. In this study, mass analysis revealed that GK921 bound to the N terminus of TGase 2 (81–116 a.a), which stabilized p53 by blocking TGase 2 binding. This suggests that RCC survival can be stopped by p53-induced cell death through blocking the p53–TGase 2 complex formation using GK921. Although GK921 does not bind to the active site of TGase 2, GK921 binding to the N terminus of TGase 2 also inactivated TGase 2 activity through acceleration of non-covalent self-polymerization of TGase 2 via conformational change. This suggests that TGase 2 has an allosteric binding site (81–116 a.a) which changes the conformation of TGase 2 enough to accelerate inactivation through self-polymer formation.
      PubDate: 2018-11-01
      DOI: 10.1007/s00726-018-2635-2
      Issue No: Vol. 50, No. 11 (2018)
  • Novel Fubinaca/Rimonabant hybrids as endocannabinoid system modulators
    • Authors: Azzurra Stefanucci; Giorgia Macedonio; Szabolcs Dvorácskó; Csaba Tömböly; Adriano Mollica
      Pages: 1595 - 1605
      Abstract: The discovery of novel modulators of the cannabinoid system is a current topic in medicinal chemistry. In this paper, we report nine novel carboxamides designed as hybrids of Fubinaca family compounds and Rimonabant. These hybrids were obtained by linking the 1-benzyl-2,5-dichloroindazole-3-carboxylic acid to different amino acids bearing a hydrophobic side chain and three different C-terminus. The new chemical entities were tested in vitro to evaluate their bioactivity by means of receptor binding assays and [35S]GTPγS stimulation assays to reveal their affinity and potency. We found that all compounds were able to bind to the cannabinoid receptors in the low nanomolar range with a marked selectivity towards the CB1 cannabinoid receptor. Some of them are full agonists, whereas the others act as partial agonists. These molecules could be potentially used as anti-obesity agents, antiemetic and analgesics.
      PubDate: 2018-11-01
      DOI: 10.1007/s00726-018-2636-1
      Issue No: Vol. 50, No. 11 (2018)
  • Structure-based design, synthesis and anticancer effect of cyclic
           Smac–polyarginine peptides
    • Authors: Melek Parlak Khalily; Selin Gerekçi; Ezgi A. Güleç; Can Özen; Salih Özçubukçu
      Pages: 1607 - 1616
      Abstract: The second mitochondria-derived activator of caspase (Smac/DIABLO) is a pro-apoptotic protein that released from mitochondria into the cytosol when cells undergo apoptosis. Smac promotes caspase activation by binding the inhibitors of apoptosis proteins (IAP), particularly XIAP and eliminating their inhibitory activity. Although the seven N-terminal amino acids AVPIAQK (SmacN7) of Smac protein is able to elicit an anticancer response by itself, it is neither cell-permeable nor stable in the cellular environment. Thus, the use of SmacN7 derivatives and mimetics is an alluring field for cancer therapy. In this study, heptamer Smac peptide was fused to a well-known octaarginine cell-penetrating peptide for promoting its intracellular access. Both therapeutic Smac part and cell-penetrating octaarginine parts of the peptide sequence constrained in a cyclic structure so as to enhance the apoptosis-inducing potential of the SmacN7 peptide. Biological assays interestingly showed that cyclic peptides P4, P5 and P7 gave rise to a significant level of cytotoxicity and apoptosis mediated cell death in multiple myeloma tumor cells (MM) comparing to linear peptide.
      PubDate: 2018-11-01
      DOI: 10.1007/s00726-018-2637-0
      Issue No: Vol. 50, No. 11 (2018)
  • Comparison of the antibacterial effects of a short cationic peptide and 1%
           silver bioactive glass against extensively drug-resistant bacteria,
           Pseudomonas aeruginosa and Acinetobacter baumannii , isolated from burn
    • Authors: Mehrdad Moosazadeh Moghaddam; Mohamad Eftekhary; Soroor Erfanimanesh; Ali Hashemi; Vahid Fallah Omrani; Behrouz Farhadihosseinabadi; Zohreh Lasjerdi; Majid Mossahebi-Mohammadi; Narendra Pal Singh Chauhan; Alexander M. Seifalian; Mazaher Gholipourmalekabadi
      Pages: 1617 - 1628
      Abstract: We have already established that a short cationic peptide (CM11) has high antimicrobial activity against a number of bacterial pathogens. Considering the untreatable problem of burn infections caused by Pseudomonas aeruginosa and Acinetobacter baumannii, this study evaluated and compared antibacterial effects of the CM11 peptide and 1% silver-doped bioactive glass (AgBG) against extensively drug-resistant strains of these bacteria which were isolated from burn patients. Accordingly, the bacteria were isolated from burn patients and their antibiotic resistance patterns and mechanisms were fully determined. The isolated bacterial from patients were resistant to almost all commonly used antibiotics and silver treatment. The isolates acquired their resistance through inactivation of their porin, the overexpression of efflux pump, and beta-lactamase. CM11 peptide and 1% AgBG had minimum inhibitory concentration (MIC) of ≥ 16 μg ml−1 and ≥ 4 mg ml−1 for clinical isolates, respectively. The minimum bactericidal concentration (MBC) of peptide and 1% AgBG for resistant bacteria was ≥ 32 μg ml−1 and ≥ 4 mg ml−1, respectively. Among the clinical isolates, two P. aeruginosa isolates and one A. baumannii isolate were resistant to 1% AgBG disk. The CM11 peptide also showed high biocompatibility in vivo and no cytotoxicity against fibroblasts and adipose-derived mesenchymal stem cells in concentrations ≤ 64 μg ml−1 and ≤ 32 μg ml−1, respectively, while the safe concentration of 1% AgBG for these cells was ≤ 16 μg ml−1. In conclusion, these findings indicated that the 1% silver is not safe and effective for treatment of such infections. The data suggest that CM11 peptide therapy is a reliable and safe strategy that can be used for the treatment of burn infections caused by antimicrobial-resistant isolates. The next stage of the study will be a multicenter clinical trial.
      PubDate: 2018-11-01
      DOI: 10.1007/s00726-018-2638-z
      Issue No: Vol. 50, No. 11 (2018)
  • Metabolic relevance for N -hydroxy l -arginine reduction in
           estrogen-negative breast cancer cells
    • Authors: Srinidi Mohan; Seema Patel; Ian Greenstein; Cathy Ng; Kelly Frazier; Giang Nguyen; Lisa Harding; David Barlow
      Pages: 1629 - 1636
      Abstract: We had shown Nw-hydroxy-l-arginine (NOHA) as a promising blood-based biomarker for estrogen-receptor-negative (ER−) breast cancer (BC) that differentiates ER− BC based on grade and molecular phenotype. In this in vitro study, we assessed the metabolic relevance for ER− BC-specific NOHA modulation and correlated them with NOHA regulatory responses. This study aids future NOHA clinical utility in ER− BC diagnosis and therapy management and would prove useful for potential drug discovery and development process.
      PubDate: 2018-11-01
      DOI: 10.1007/s00726-018-2603-x
      Issue No: Vol. 50, No. 11 (2018)
  • Taurine regulates mucosal barrier function to alleviate
           lipopolysaccharide-induced duodenal inflammation in chicken
    • Authors: Min Xiao; Yuling Mi; Lijuan Liu; Caifeng Lv; Weidong Zeng; Caiqiao Zhang; Jian Li
      Pages: 1637 - 1646
      Abstract: The objective of the study was to investigate how taurine alleviates mucosal injury. Young chickens were fed with taurine for 1 week and then challenged with lipopolysaccharide. We found that, under lipopolysaccharide challenge, taurine could attenuate diarrhea and mucosal inflammation. Additionally, under LPS challenge, taurine could enhance epithelial proliferation and goblet cell function, could also decrease epithelial apoptosis by improving the mitochondrial membrane permeability. The high-performance liquid chromatography assay showed that taurine feeding could elevate taurine concentration in duodenum obviously. The antioxidant assay showed that taurine could reverse lipopolysaccharide-induced low GSH level, GSH/GSSG ratio, GSH-Px activity and SOD activity, high GSSG and MDA content. In summary, we suggested that taurine could enhance duodenal antioxidant status locally and further ameliorated lipopolysaccharide-induced chicken duodenal inflammation by improving mitochondrial membrane permeability and goblet cell function.
      PubDate: 2018-11-01
      DOI: 10.1007/s00726-018-2631-6
      Issue No: Vol. 50, No. 11 (2018)
  • Correction to: Ten weeks of branched-chain amino acid supplementation
           improves select performance and immunological variables in trained
    • Authors: Wesley C. Kephart; Taylor D. Wachs; R. Mac Thompson; C. Brooks Mobley; Carlton D. Fox; James R. McDonald; Brian S. Ferguson; Kaelin C. Young; Ben Nie; Jeffrey S. Martin; Joseph M. Company; David D. Pascoe; Robert D. Arnold; Jordan R. Moon; Michael D. Roberts
      Pages: 1495 - 1495
      Abstract: For the author R. Mac Thompson, the first name should be R. Mac and the last name should be Thompson. On SpringerLink the name is listed correctly, but on PubMed he is listed as Mac Thompson R.
      PubDate: 2018-10-01
      DOI: 10.1007/s00726-018-2632-5
      Issue No: Vol. 50, No. 10 (2018)
  • Novel, efficient, facile, and comprehensive protocol for post-column amino
           acid analysis of icatibant acetate containing natural and unnatural amino
           acids using the QbD approach
    • Authors: Yagnakirankumar Komaravolu; Venugopala Rao Dama; Thirumala Chary Maringanti
      Abstract: Qualitative and quantitative determination of amino acid composition using amino acid analysis (AAA) is an important quality attribute and considered an identity of therapeutic peptide drugs by the regulatory agencies. Although huge literature is available on pre- and post- column derivatization AAA methods, arriving at an appropriate hydrolysis protocol coupled with adequate separation of the derivatized/underivatized amino acids is always challenging. Towards achieving a facile and comprehensive protocol for AAA, the present work is geared towards developing a deeper understanding of the extent of hydrolysis of peptide, and the nature and stability of amino acids present in the peptide backbone. This defines the suitability of the method in meeting the end goals and the regulatory requirement. Analysis of historical data generated during the method optimization of AAA for icatibant acetate (ICT) using head space oven hydrolysis (HSOH) and microwave-assisted hydrolysis (MAH) methods helped in arriving at fast (< 1 h) and efficient hydrolysis (0.9–1.1 of theoretical residue) conditions. Better separations for the natural and unnatural amino acids were achieved using 3.45 ≤ pH ≤ 10.85, and a column oven gradient program. This approach was useful in meeting the method quality attributes [resolution (Rs) > 2.0; plate count (N) > 5600; and USP tailing factor < 1.2] with a target analytical method profile of relative amino acid mole ratios (RAAMR) in the range of 0.9–1.1 for Ser, Oic, Tic, Hyp, Ala (Thi), Gly and Pro, and between 2.7 and 3.3 for Arg. The developed method was validated as per the ICH guidelines and is precise, accurate, linear and robust.
      PubDate: 2018-10-16
      DOI: 10.1007/s00726-018-2665-9
  • The self-disproportionation of enantiomers (SDE) of α-amino acid
           derivatives: facets of steric and electronic properties
    • Authors: Takuma Hosaka; Tomomi Imai; Alicja Wzorek; Magdalena Marcinkowska; Anna Kolbus; Osamu Kitagawa; Vadim A. Soloshonok; Karel D. Klika
      Abstract: α-Amino acids (α-AAs) are in extremely high demand in nearly every sector of the food and health-related chemical industries and continue to be the subject of intense multidisciplinary research. The self-disproportionation of enantiomers (SDE) is an emerging and one of the least studied areas of α-AA or enantiomeric properties, critically important for their production and application. In the present work, we report a detailed study of the SDE via achiral, gravity-driven column chromatography for a set of N-acylated, N-carbonylated, N-fluoroacylated, and N-thioacylated α-amino acid esters. As well as thioacylation, attention was paid to the effect of altering the R group of the ester functionality, the side chain, or that of the acyl group attached to the amide nitrogen, whereby it was found that electron-withdrawing groups in the latter moiety had a pronounced effect on the magnitude and behavior of the resulting SDE phenomenon. Intriguingly, in the case of N-fluoroacylated derivatives, by favoring the formation of dimeric associates and effecting a strong bias toward homochiral associates over heterochiral associates, the SDE magnitude was greatly reduced contrary to intuitive expectations. Energy estimates resulted from DFT calculations.
      PubDate: 2018-10-11
      DOI: 10.1007/s00726-018-2664-x
  • Development and validation of a sensitive LC–MS/MS assay for the
           quantification of anserine in human plasma and urine and its application
           to pharmacokinetic study
    • Authors: Inge Everaert; Giovanna Baron; Silvia Barbaresi; Ettore Gilardoni; Crescenzo Coppa; Marina Carini; Giulio Vistoli; Tine Bex; Jan Stautemas; Laura Blancquaert; Wim Derave; Giancarlo Aldini; Luca Regazzoni
      Abstract: Carnosine (beta-alanyl-l-histidine) and its methylated analogue anserine are present in relevant concentrations in the omnivore human diet. Several studies reported promising therapeutic potential for carnosine in various rodent models of oxidative stress and inflammation-related chronic diseases. Nevertheless, the poor serum stability of carnosine in humans makes the translation of rodent models hard. Even though anserine and carnosine have similar biochemical properties, anserine has better serum stability. Despite this interesting profile, the research on anserine is scarce. The aim of this study was to explore the bioavailability and stability of synthesized anserine by (1) performing in vitro stability experiments in human plasma and molecular modelling studies and by (2) evaluating the plasma and urinary pharmacokinetic profile in healthy volunteers following different doses of anserine (4–10–20 mg/kg body weight). A bio-analytical method for measuring anserine levels was developed and validated using liquid chromatography-electrospray mass spectrometry. Both plasma (CMAX: 0.54–1.10–3.12 µM) and urinary (CMAX: 0.09–0.41–0.72 mg/mg creatinine) anserine increased dose-dependently following ingestion of 4–10–20 anserine mg/kg BW, respectively. The inter-individual variation in plasma anserine was mainly explained by the activity (R2 = 0.75) and content (R2 = 0.77) of the enzyme serum carnosinase-1. Compared to carnosine, a lower interaction energy of anserine with carnosinase-1 was suggested by molecular modelling studies. Conversely, the two dipeptides seems to have similar interaction with the PEPT1 transporter. It can be concluded that nutritionally relevant doses of synthesized anserine are well-absorbed and that its degradation by serum carnosinase-1 is less pronounced compared to carnosine. This makes anserine a good candidate as a more stable carnosine-analogue to attenuate chronic diseases in humans.
      PubDate: 2018-10-09
      DOI: 10.1007/s00726-018-2663-y
  • Fragments of the second transmembrane helix of three G-protein-coupled
           receptors: comparative synthetic, structural and conformational studies
    • Authors: Douglas D. Lopes; Jamille H. Cuvero; Mariana M. L. Ferreira; Rogério L. Silva; Sinval E. G. Souza; Luciana Malavolta; Shirley Schreier; Clovis R. Nakaie
      Abstract: We compared the synthesis and structural/conformational details of the (66–97) segments of the second transmembrane helix of AT1, MAS and B2, all of which belong to the class of G-protein-coupled receptors (GPCR). Step-by-step monitoring of the coupling reactions during the growth of these transmembrane peptides revealed that the increase in the level of difficulty started at the 6–10 regions of the sequence. Possibly due to their long and hydrophobic sequences, the final estimated synthesis yields decreased progressively by up to 20–25%. Analytical high pressure liquid chromatography showed that the hydrophobicity indexes of each TM-8, -16, -24 and -32 segments correlated linearly with their retention time. Microscopic measurements of peptide–resin beads indicated that, in general, dichloromethane and dimethylsulfoxide were the best solvents for solvating resin beads in the initial and final stages of the synthesis, respectively. Results from electron paramagnetic resonance experiments with Toac (2, 2, 6, 6-tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid) spin-labeled peptide resins revealed that the level of peptide chain mobility throughout the polymer network was in agreement with their swelling data measured in different solvents. Initial results regarding conformational features determined by circular dichroism (CD) spectra revealed typical α-helicoidally structures for MAS and B2 TM32 fragments when in more than roughly 30% (v/v) trifluoroethanol (TFE). In contrast, the AT1-TM32 segment revealed CD spectra, more representatives of a mixture of other secondary helical conformers, regardless of the amount of TFE. These findings observed in different aspects of these receptors’ fragments support further investigations of GPCR-type macromolecules.
      PubDate: 2018-10-08
      DOI: 10.1007/s00726-018-2662-z
  • A conformationally restricted GABA analogue based on octahydro-1 H
           -cyclopenta[ b ]pyridine scaffold
    • Authors: Kostiantyn P. Melnykov; Dmitriy M. Volochnyuk; Sergey V. Ryabukhin; Eduard B. Rusanov; Oleksandr O. Grygorenko
      Abstract: An approach to rel-(4aS,6R,7aR)-octahydro-1H-cyclopenta[b]pyridine-6-carboxylic acid—a bicyclic conformationally restricted γ-aminobutyric acid (GABA) analogue was developed. The eight-step sequence relied on the reaction of 2,3-bis(chloromethyl)pyridine and a C1-binucleophile and the catalytic reduction of the pyridine ring as the key steps and allowed for the preparation of the title compound in 9.0% overall yield. Assessment of the octahydro-1H-cyclopenta[b]pyridine scaffold geometry showed that this template can be considered truly three-dimensional.
      PubDate: 2018-10-04
      DOI: 10.1007/s00726-018-2660-1
  • Ensembling three multicomponent reactions for the synthesis of a novel
           category of pseudo-peptides containing dithiocarbamate and N , X
           -heterocylic groups
    • Authors: Maryam Khalesi; Azim Ziyaei Halimehjani; Max Franz; Marc Schmidtmann; Jürgen Martens
      Abstract: Consecutive multicomponent reactions have been applied for the synthesis of novel pseudo-peptides bearing dithiocarbamate and N,X-heterocyclic groups (X = S, O) in only one structure. The first multicomponent reaction includes the synthesis of dithiocarbamates using an amine or amino acid, CS2 and an electrophile. The second MCR is synthesis of Asinger imines using 2-chloroisobutyraldehyde, NaXH (X = S, O), ketone and ammonia. The final MCR is Ugi reaction to afford the corresponding three-dimensional pseudo-peptides. Various Asinger imines, carboxylic acids and isocyanides were applied in this protocol to provide diversities of pseudo-peptides in high to excellent yields.
      PubDate: 2018-10-04
      DOI: 10.1007/s00726-018-2661-0
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