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Amino Acids

Alexander Bollenbach, Dimitrios Tsikas
Asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) are endogenous inhibitors of nitric oxide (NO) synthase. SDMA is excreted in the urine without major metabolization. About 10% of daily produced ADMA are excreted unchanged in the urine. The major elimination route of ADMA (about 90%) involves its hydrolysis to dimethylamine (DMA) and L-citrulline by dimethylarginine dimethylaminohydrolase (DDAH) and excretion of DMA in the urine. High circulating and low excretory concentrations of ADMA are considered risk factors...
December 8, 2018: Amino Acids
Mrinmoy Ghosh, Neelesh Sharma, Meeta Gera, Nameun Kim, Simrinder Singh Sodhi, KrishnaKanth Pulicherla, Do Huynh, Dae Cheol Kim, Jiaojiao Zhang, Taeho Kwon, Kyung Tak Do, Hak Kyo Lee, Ki-Duk Song, DongKee Jeong
Sus scrofa provides a major source of animal protein for humans as well as being an excellent biomedical model. This study was carried out to understand, in detail, the genetic and functional variants of Jeju Native Pigs and miniature pigs through differential expression profiling of the genes controlling their immune response, growth performance, and meat quality. The Illumina HiSeq 2000 platform was used for generating 1.3 billion 90 bp paired-end reads, which were mapped to the S. scrofa genome using TopHat2...
December 5, 2018: Amino Acids
Oliviero Carugo
Proteins are not static molecules but dynamic entities able to modify their structure for several reasons, from the necessity to recognize partners to the regulation of their thermodynamic stability. Conformational disorder is frequent in protein structures and atoms can have, in protein crystal structures, two or more alternative, equilibrium positions close to each other. Here, a set of protein crystal structures refined at very high resolution (1 Å or better) is examined to characterize the conformational disorder of the backbone atoms, which is not infrequent: about 15% of the protein backbone atoms are conformationally disordered and three quarters of them have been deposited with two or more equilibrium positions (most of the others were not detected in the electron density maps)...
December 4, 2018: Amino Acids
Xiaoxiao Fan, Shuai Li, Zhenlong Wu, Zhaolai Dai, Ju Li, Xiaolong Wang, Guoyao Wu
This study was conducted to test the hypothesis that preweaning  glycine supplementation to breast-fed piglets alleviated the post-weaning  apoptosis of jejunal epithelium through CHOP signaling. Seven-day-old sow-reared piglets were orally administrated with 0, 50, 100, or 200% of glycine intake from sow's milk twice daily for 14 days and then were weaned at 21 days of age. Tissue samples were collected at 28 days of age for determining intestinal morphology, serum diamine oxidase (DAO) activity, abundances of proteins involved in ER stress and apoptosis...
November 28, 2018: Amino Acids
Jingjing Zhao, Dheeraj Kumar Posa, Vijay Kumar, David Hoetker, Amit Kumar, Smirthy Ganesan, Daniel W Riggs, Aruni Bhatnagar, Michael F Wempe, Shahid P Baba
Endogenous histidyl dipeptides such as carnosine (β-alanine-L-histidine) form conjugates with lipid peroxidation products such as 4-hydroxy-trans-2-nonenal (HNE and acrolein), chelate metals, and protect against myocardial ischemic injury. Nevertheless, it is unclear whether these peptides protect against cardiac injury by directly reacting with lipid peroxidation products. Hence, to examine whether changes in the structure of carnosine could affect its aldehyde reactivity and metal chelating ability, we synthesized methylated analogs of carnosine, balenine (β-alanine-Nτ -methylhistidine) and dimethyl balenine (DMB), and measured their aldehyde reactivity and metal chelating properties...
November 17, 2018: Amino Acids
Andressa Cristina Antunes Santos, Cristina Bichels Hebeba, Araceli Aparecida Hastreiter, Dalila Cunha de Oliveira, Edson Naoto Makiyama, Sandra Helena Poliselli Farsky, Primavera Borelli, Ricardo Ambrosio Fock
Glutamine (GLN) is the most abundant free amino acid in the body, and is considered as a conditionally essential amino acid under stress conditions, acting as an important modulator of the immune response. We here investigated the role of exogenous GLN treatment on leukocyte migration after the onset of endotoxemia and the intracellular mechanisms of GLN actions on neutrophils. Two in vivo models of endotoxemia caused by lipopolysaccharide of Escherichia coli (LPS) injection were carried out in male outbred Balb/C mice 2-3 months old, as follow: (1) LPS (50 μg/kg) was intravenously injected 1 h prior to intravenous injection of GLN (0...
November 17, 2018: Amino Acids
Yoshinori Tokairin, Vadim A Soloshonok, Hiroki Moriwaki, Hiroyuki Konno
Practical new routes for preparation of (2S,3S)-3-Me-glutamine and (R)-allo-threonine derivatives, the key structural components of cytotoxic marine peptides callipeltin O and Q, suitable for the Fmoc-SPPS, were developed. (2S,3S)-Fmoc-3-Me-Gln(Xan)-OH was synthesized via Michael addition reactions of Ni (II) complex of chiral Gly-Schiff base; while Fmoc-(R)-allo-Thr-OH was prepared using chiral Ni (II) complex-assisted α-epimerization methodology, starting form (S)-Thr(tBu)-OH.
November 17, 2018: Amino Acids
Srinidi Mohan, Seema Patel, Ian Greenstein, Cathy Ng, Kelly Frazier, Giang Nguyen, Lisa Harding, David Barlow
We found a unit error with our LC-MS lower limit of quantitation (LLOQ) measurement in the Amino Acids Journal.
November 17, 2018: Amino Acids
Mostafa A L Abdel-Salam, Juliana Carvalho-Tavares, Kamila Sousa Gomes, Andrea Teixeira-Carvalho, Gregory T Kitten, Johanna Nyffeler, Felipe F Dias, Pablo V Mendes Dos Reis, Adriano M C Pimenta, Marcel Leist, Maria Elena de Lima, Elaine Maria de Souza-Fagundes
Antimicrobial peptides present a broad spectrum of therapeutic applications, including their use as anticancer peptides. These peptides have as target microbial, normal, and cancerous cells. The oncological properties of these peptides may occur by membranolytic mechanisms or non-membranolytics. In this work, we demonstrate for the first time the cytotoxic effects of the cationic alpha-helical antimicrobial peptide LyeTx I-b on glioblastoma lineage U87-MG. The anticancer property of this peptide was associated with a membranolytic mechanism...
November 17, 2018: Amino Acids
Kyungsoo Shin, Michael Landsman, Stephanie Pelletier, Bader N Alamri, Younes Anini, Jan K Rainey
Apelin is a peptide hormone that binds to a class A GPCR (the apelin receptor/APJ) to regulate various bodily systems. Upon signal peptide removal, the resulting 55-residue isoform, proapelin/apelin-55, can be further processed to 36-, 17-, or 13-residue isoforms with length-dependent pharmacological properties. Processing was initially proposed to occur intracellularly. However, detection of apelin-55 in extracellular fluids indicates that extracellular processing may also occur. To test for this, apelin-55 was applied exogenously to HEK293A cells overexpressing proprotein convertase subtilisin kexin 3 (PCSK3), the only apelin processing enzyme identified thus far, and to differentiated 3T3-L1 adipocytes, which endogenously express apelin, PCSK3 and other proprotein convertases...
November 15, 2018: Amino Acids
Katya Anaya, Nadine Sus, Carlos Gadelha, Jan Frank
Plant foods are rich sources of biologically active peptides that may have a role in the prevention of diseases. Coconut water is a valuable beverage due to its nutrient composition and the presence of bioactive compounds, such as the peptide CnAMP1. It is unknown if CnAMP1 can be absorbed into intestinal cells. We, therefore, aimed to develop and validate a simple reversed-phase liquid chromatographic method to quantify the peptide in Caco-2 and LS180 cell lysates. CnAMP1 standards (1-200 µmol/L) and spiked cell lysates were injected onto a Reprosil-Pur 120 C18-AQ column (4...
November 14, 2018: Amino Acids
Ronald Domalaon, Marc Brizuela, Benjamin Eisner, Brandon Findlay, George G Zhanel, Frank Schweizer
The necessity to develop therapeutic agents and strategies to abate the spread of antibiotic-resistant pathogens is prominent. Antimicrobial peptides (AMPs) provide scaffolds and inspiration for antibiotic development. As an AMP of shorter scaffold, eight dilipid ultrashort cationic lipopeptides (dUSCLs) were prepared consisting of only four amino acids and varying dilipids. Lipids were acylated at the peptide N-terminus and the ε-amine side chain of the N-terminal L-lysine. Compounds that possess aliphatic dilipids of ≥ 11 carbons-long showed significant hemolysis and therefore limited therapeutic application...
November 3, 2018: Amino Acids
Ljiljana Mrkus, Jelena Batinić, Nina Bjeliš, Andreja Jakas
Quercetin and resveratrol are polyphenolic compounds, members of the flavonoid and the stilbene family, respectively, both medicinally important as dietary anticancer and antioxidant agents. They are present in a variety of foods-including fruits, vegetables, tea, wine, as well as other dietary supplements-and are responsible for various health benefits. Different quercetin and resveratrol esters of Leu/Met-enkephalin and tetrapeptide Leu-Ser-Lys-Leu (LSKL) were synthesized as model systems for monitoring the influence of the peptides on biological activity of resveratrol and quercetin...
November 3, 2018: Amino Acids
Xiao-Dong Liu, Fu-Xin Zhang, Zhi-Hua Qin, Hu Shan
Anticancer peptides (ACPs) are biologically anticancer active molecules that are produced by mammals, plants, insects and microorganisms. Here, a new peptide (TC22) with the amino acid sequence MTVVLLLIVLPLLGGVHSSGIL was identified and characterized from the beetle Tribolium castaneum. We found it inhibited the growth and viability of HeLa and MCF-7 cells. Flow cytometry analysis demonstrated the TC22 induced HeLa cell apoptosis, and activated caspase-9 and caspase-3. Furthermore, TC22 led to ROS generation, and triggered p53 transcription and expression...
October 30, 2018: Amino Acids
Motoyasu Adachi, Rumi Shimizu, Shiro Kato, Tadao Oikawa
We expressed a histidine racemase from Leuconostoc mesenteroides subsp. sake NBRC 102480 (Lm-HisR) successively in a soluble fraction of Escherichia coli BL21 (DE3) and then highly purified it from the cell-free extract. Lm-HisR showed amino acid racemase activity on histidine specifically. This is the first example of an amino acid racemase specifically acting on histidine. Phylogenetic analysis of Lm-HisR showed that Lm-HisR was located far from the cluster of alanine racemases reported thus far and only in lactic acid bacteria of the genus Leuconostoc...
October 30, 2018: Amino Acids
Akinkunmi Paul Okekunle, Xiaoyan Wu, Rennan Feng, Ying Li, Changhao Sun
We assessed the relationship between energy-adjusted amino acids (EAA) intakes and obesity risk using data on nutrient intakes derived from the Chinese food composition tables to determine dietary intakes (DI) among 1109 obese and 3009 normal weight subjects. Dietary patterns (DP) were identified using principal component analysis, multivariable-adjusted odds ratio (OR) and 95% confidence interval (CI) of obesity risk by quartiles of EAA intakes was estimated using logistic regression with two-sided P < 0...
October 30, 2018: Amino Acids
Carlos Alberto Zanutto Bassetto Junior, Luana Vitorino Gushiken Passianoto, Eduardo René Pérez González, Wamberto Antonio Varanda
KV 3.1 blockers can serve as modulators of the rate of action potential firing in neurons with high rates of firing such as those of the auditory system. We studied the effects of several bioisosteres of N-alkylbenzenesulfonamides, and molecules derived from sulfanilic acid on KV 3.1 channels, heterologously expressed in L-929 cells, using the whole-cell patch-clamp technique. Only the N-alkyl-benzenesulfonamides acted as open-channel blockers on KV 3.1, while molecules analogous to PABA (p-aminobenzoic acid) and derived from sulfanilic acids did not block the channel...
October 25, 2018: Amino Acids
Mingqiang Rong, Jie Liu, Qiong Liao, Zhilong Lin, Bo Wen, Yan Ren, Ren Lai
The diversity of defensive peptides from skin of amphibians has been demonstrated. These peptides may have resulted from the diversity of microorganisms encountered by amphibians. In this study, peptidomics and RNA sequencing analyses were used to study deeply the defensive peptides of the skin secretions from Polypedates megacephalus. A total of 99 defensive peptides have been identified from the skin secretions. Among these peptides, 3 peptides were myotropical peptides and 34 peptides classified as protease inhibitor peptides...
October 23, 2018: Amino Acids
D S Berezhnoy, S L Stvolinsky, A V Lopachev, A A Devyatov, O M Lopacheva, O I Kulikova, D A Abaimov, T N Fedorova
Carnosine (b-alanyl-L-histidine) is an endogenous dipeptide widely distributed in excitable tissues, such as muscle and neural tissues-though in minor concentrations in the latter. Multiple benefits have been attributed to carnosine: direct and indirect antioxidant effect, antiglycating, metal-chelating, chaperone and pH-buffering activity. Thus, carnosine turns out to be a multipotent protector against oxidative damage. However, the role of carnosine in the brain remains unclear. The key aspects concerning carnosine in the brain reviewed are as follows: its concentration and bioavailability, mechanisms of action in neuronal and glial cells, beneficial effects in human studies...
October 23, 2018: Amino Acids
Yagnakirankumar Komaravolu, Venugopala Rao Dama, Thirumala Chary Maringanti
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...
October 16, 2018: Amino Acids
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