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https://www.readbyqxmd.com/read/28095360/enzyme-catalyzed-michael-addition-for-the-synthesis-of-warfarin-and-its-determination-via-fluorescence-quenching-of-l-tryptophan
#1
Yusheng Yuan, Liu Yang, Shaopu Liu, Jidong Yang, Hui Zhang, Jingjing Yan, Xiaoli Hu
A sensitive fluorescence sensor for warfarin was proposed via quenching the fluorescence of l-tryptophan due to the interaction between warfarin and l-tryptophan. Warfarin, as one of the most effective anticoagulants, was designed and synthesized via lipase from porcine pancreas (PPL) as a biocatalyst to catalyze the Michael addition of 4-hydroxycoumarin to α, β-unsaturated enones in organic medium in the presence of water. Furthermore, the spectrofluorometry was used to detect the concentration of warfarin with a linear range and detection limit (3σ/k) of 0...
January 9, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28089858/glucose-amino-acids-and-fatty-acids-directly-regulate-ghrelin-and-nucb2-nesfatin-1-in-the-intestine-and-hepatopancreas-of-goldfish-carassius-auratus-in-vitro
#2
Juan Ignacio Bertucci, Ayelén Melisa Blanco, Luis Fabián Canosa, Suraj Unniappan
Ghrelin and nesfatin-1 are two peptidyl hormones primarily involved in food intake regulation. We previously reported that the amount of dietary carbohydrates, protein and lipids modulates the expression of these peptides in goldfish in vivo. In the present work, we aimed to characterize the effects of single nutrients on ghrelin and nesfatin-1 in the intestine and hepatopancreas. First, immunolocalization of ghrelin and NUCB2/nesfatin-1 in goldfish hepatopancreas cells was studied by immunohistochemistry. Second, the effects of 2 and 4h-long exposures of cultured intestine and hepatopancreas sections to glucose, L-tryptophan, oleic acid, linolenic acid (LNA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on ghrelin and nesfatin-1 gene and protein expression were studied...
January 13, 2017: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
https://www.readbyqxmd.com/read/28076364/ifn%C3%AE-regulates-activated-v%C3%AE-2-t-cells-through-a-feedback-mechanism-mediated-by-mesenchymal-stem-cells
#3
Karoline Fechter, Akaitz Dorronsoro, Emma Jakobsson, Izaskun Ferrin, Valérie Lang, Pilar Sepulveda, Daniel J Pennington, César Trigueros
γδ T cells play a role in a wide range of diseases such as autoimmunity and cancer. The majority of circulating human γδ T lymphocytes express a Vγ9Vδ2+ (Vδ2+) T cell receptor (TCR) and following activation release pro-inflammatory cytokines. In this study, we show that IFNγ, produced by Vδ2+ cells, activates mesenchymal stem cell (MSC)-mediated immunosupression, which in turn exerts a negative feedback mechanism on γδ T cell function ranging from cytokine production to proliferation. Importantly, this modulatory effect is limited to a short period of time (<24 hours) post-T cell activation, after which MSCs can no longer exert their immunoregulatory capacity...
2017: PloS One
https://www.readbyqxmd.com/read/28032983/two-flavoenzymes-catalyze-the-post-translational-generation-of-5-chlorotryptophan-and-2-aminovinyl-cysteine-during-nai-107-biosynthesis
#4
Manuel A Ortega, Dillon P Cogan, Subha Mukherjee, Neha Garg, Bo Li, Gabrielle N Thibodeaux, Sonia I Maffioli, Stefano Donadio, Margherita Sosio, Jerome Escano, Leif Smith, Satish K Nair, Wilfred A van der Donk
Lantibiotics are ribosomally synthesized and post-translationally modified antimicrobial peptides containing thioether rings. In addition to these cross-links, the clinical candidate lantibiotic NAI-107 also possesses a C-terminal S-[(Z)-2-aminovinyl]-d-cysteine (AviCys) and a unique 5-chloro-l-tryptophan (ClTrp) moiety linked to its potent bioactivity. Bioinformatic and genetic analyses on the NAI-107 biosynthetic gene cluster identified mibH and mibD as genes encoding flavoenzymes responsible for the formation of ClTrp and AviCys, respectively...
January 13, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/27998091/tryptophan-lyase-nosl-a-cornucopia-of-5-deoxyadenosyl-radical-mediated-transformations
#5
Dhananjay M Bhandari, Dmytro Fedoseyenko, Tadhg P Begley
Tryptophan lyase (NosL) is a radical S-adenosyl-l-methionine (SAM) enzyme that catalyzes the formation of 3-methyl-2-indolic acid from l-tryptophan. In this paper, we demonstrate that the 5'-deoxyadenosyl radical is considerably more versatile in its chemistry than previously anticipated: hydrogen atom abstraction from Nα-cyclopropyltryptophan occurs at Cα rather than the amino group with NosL Y90A and replacing the substrate amine with a ketone or an alkene changes the chemistry from hydrogen atom abstraction to double bond addition...
December 21, 2016: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/27997749/inhibition-of-platelet-aggregation-and-thrombosis-by-indole-alkaloids-isolated-from-the-edible-insect-protaetia-brevitarsis-seulensis-kolbe
#6
JungIn Lee, Wonhwa Lee, Mi-Ae Kim, Jae Sam Hwang, MinKyun Na, Jong-Sup Bae
Protaetia brevitarsis seulensis (Kolbe) has been temporarily registered as a food material by the Ministry of Food and Drug Safety of Korea (MFDS). The current study aimed to discover small antithrombotic molecules from this edible insect. Five indole alkaloids, 5-hydroxyindolin-2-one (1), (1R,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (2), (1S,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (3), (3S)-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (4) and L-tryptophan (5), were isolated from the insect...
December 20, 2016: Journal of Cellular and Molecular Medicine
https://www.readbyqxmd.com/read/27994758/fused-heterocyclic-compounds-as-potent-indoleamine-2-3-dioxygenase-1-inhibitors
#7
Subhankar Panda, Ashalata Roy, Suman Jyoti Deka, Vishal Trivedi, Debasis Manna
Uncontrolled metabolism of l-tryptophan (l-Trp) in the immune system has been recognized as a critical cellular process in immune tolerance. Indoleamine 2,3-dioxygenase 1 (IDO1) enzyme plays an important role in the metabolism of a local l-Trp through the kynurenine pathway in the immune systems. In this regard, IDO1 has emerged as a therapeutic target for the treatment of diseases that are associated with immune suppression like chronic infections, cancer, and others. In this study, we synthesized a series of pyridopyrimidine, pyrazolopyranopyrimidine, and dipyrazolopyran derivatives...
December 8, 2016: ACS Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/27988124/increased-serum-serotonin-improves-parturient-calcium-homeostasis-in-dairy-cows
#8
Lorenzo E Hernández-Castellano, Laura L Hernandez, Samantha Weaver, Rupert M Bruckmaier
Hypocalcemia in dairy cows is caused by the sudden increase in calcium demand by the mammary gland for milk production at the onset of lactation. Serotonin (5-HT) is a key factor for calcium homeostasis, modulating calcium concentration in blood. Therefore, it is hypothesized that administration of 5-hydroxy-l-tryptophan (5-HTP), a 5-HT precursor, can increase 5-HT concentrations in blood and, in turn, induce an increase in blood calcium concentration. In this study, 20 Holstein dairy cows were randomly assigned to 2 experimental groups...
December 14, 2016: Journal of Dairy Science
https://www.readbyqxmd.com/read/27951658/analysis-of-reaction-intermediates-in-tryptophan-2-3-dioxygenase-a-comparison-with-indoleamine-2-3-dioxygenase
#9
Jaswir Basran, Elizabeth S Booth, Michael Lee, Sandeep Handa, Emma L Raven
Indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) are heme-containing enzymes that catalyze the O2-dependent oxidation of l-tryptophan (l-Trp) in biological systems. Although many decades have passed since their discovery, the mechanism of tryptophan oxidation has not been established. It has been widely assumed that IDO and TDO react using the same mechanism, although there is no evidence that they do. For IDO, a Compound II (ferryl) species accumulates in the steady state and is implicated in the mechanism; in TDO, no such species has ever been observed...
December 13, 2016: Biochemistry
https://www.readbyqxmd.com/read/27943428/synthesis-of-2-mercaptoacetyl-l-2-14-c-tryptophan-as-a-selective-metallo-%C3%AE-lactamase-inhibitor-via-2-14-c-indole-based-on-chiral-pool-strategy
#10
Gholamhossein Shirvani, Abbas Shockravi, Mohsen Amini, Nader Saemian
Metallo-beta-lactamase enzymes make bacteria resistant to a broad range of commonly used beta-lactam antibiotics. Several thiol derivatives of L-amino acids have been shown their inhibitory effects against the metallo-β-lactamase IMP-1. In this study, (2-mercaptoacetyl)-L-tryptophan as a new inhibitor of MBLs labeled with carbon-14 in the 2-position of the indole ring was prepared from [2-(14) C]indole as a key synthetic intermediate based on chiral pool strategy. The overall synthesis was carried out in ten-step with the overall radiochemical yield 3...
December 12, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
https://www.readbyqxmd.com/read/27942644/chiral-organocatalysts-based-on-lipopeptide-micelles-for-aldol-reactions-in-water
#11
B M Soares, A M Aguilar, E R Silva, M D Coutinho-Neto, I W Hamley, M Reza, J Ruokolainen, W A Alves
A comprehensive study of the self-assembly in water of a lipopeptide consisting of a sequence of l-proline, l-arginine and l-tryptophan with a hydrocarbon chain has been performed. Fluorescence assays were used to determine the critical aggregation concentration. In situ small-angle X-ray scattering (SAXS) and molecular dynamics simulations showed the presence of spherical micelles with diameters around 6 nm. In agreement with these results, cryo-TEM images showed globular aggregates with diameters ranging from ≈4 nm up to ≈9 nm...
January 4, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27935677/tryptophan-synthase-uses-an-atypical-mechanism-to-achieve-substrate-specificity
#12
Andrew R Buller, Paul van Roye, Javier Murciano-Calles, Frances H Arnold
Tryptophan synthase (TrpS) catalyzes the final steps in the biosynthesis of l-tryptophan from l-serine (Ser) and indole-3-glycerol phosphate (IGP). We report that native TrpS can also catalyze a productive reaction with l-threonine (Thr), leading to (2S,3S)-β-methyltryptophan. Surprisingly, β-substitution occurs in vitro with a 3.4-fold higher catalytic efficiency for Ser over Thr using saturating indole, despite a >82000-fold preference for Ser in direct competition using IGP. Structural data identify a novel product binding site, and kinetic experiments clarify the atypical mechanism of specificity: Thr binds efficiently but decreases the affinity for indole and disrupts the allosteric signaling that regulates the catalytic cycle...
December 27, 2016: Biochemistry
https://www.readbyqxmd.com/read/27934657/the-importance-of-quality-specifications-in-safety-assessments-of-amino-acids-the-cases-of-l-tryptophan-and-l-citrulline
#13
REVIEW
Hellen A Oketch-Rabah, Amy L Roe, Bill J Gurley, James C Griffiths, Gabriel I Giancaspro
The increasing consumption of amino acids from a wide variety of sources, including dietary supplements, natural health products, medical foods, infant formulas, athletic and work-out products, herbal medicines, and other national and international categories of nutritional and functional food products, increases the exposure to amino acids to amounts far beyond those normally obtained from the diet, thereby necessitating appropriate and robust safety assessments of these ingredients. Safety assessments of amino acids, similar to all food constituents, largely rely on the establishment of an upper limit [Tolerable Upper Intake Level (UL)] considered to be a guide for avoiding high intake, above which adverse or toxic effects might occur...
December 2016: Journal of Nutrition
https://www.readbyqxmd.com/read/27930920/indoleamine-2-3-dioxygenase-regulates-t-cell-activity-through-vav1-rac-pathway
#14
Runmei Li, Hui Li, Qian Sun, Liang Liu, Chen Zhang, Xiubao Ren
The immunoregulatory enzyme indoleamine 2,3-dioxygenase (IDO) suppresses T-cell responses and promotes immune tolerance in tumor resistance. A previous study determined that IDO inhibits Vav1 mRNA expression and the activation of Vav1 and its downstream targets in T cells in the guanine exchange factor (GEF)-independent pathway. The current study aims to determine whether IDO induces T-cell immunosuppression through Vav1/Rac signaling pathway, which is a GEF-dependent pathway. The correlation between Vav1 mRNA expressions in T cells of tumor infiltrating lymphocytes and the levels of IDO expression in lung cancer tissues from lung cancer patients was detected...
January 2017: Molecular Immunology
https://www.readbyqxmd.com/read/27920887/preliminary-study-on-cost-effective-l-tryptophan-production-from-indole-and-l-serine-by-e-coli-cells
#15
Tahereh Sadeghiyan-Rizi, Jamshid Fooladi, Sima Sadrai
BACKGROUND: L-tryptophan is used widespread in the pharmaceutical industry. The majority of L-Trp production depends on microbial processes that produce L-tryptophan from indole and L-serine. These processes are very costly due to the costs of precursors, especially L-serine. Use of inexpensive substitutions as the L-serine source of L-tryptophan production enables us to reach a cost-effective process. In this paper, effect of Triton X-100 on L-Trp production and the ability to use Iranian cane molasses as inexpensive L-serine source was investigated...
October 2016: Avicenna Journal of Medical Biotechnology
https://www.readbyqxmd.com/read/27916541/the-orphan-g-protein-coupled-receptor-gpr139-is-activated-by-the-peptides-adrenocorticotropic-hormone-acth-%C3%AE-and-%C3%AE-melanocyte-stimulating-hormone-%C3%AE-msh-and-%C3%AE-msh-and-the-conserved-core-motif-hfrw
#16
Anne Cathrine Nøhr, Mohamed A Shehata, Alexander S Hauser, Vignir Isberg, Jacek Mokrosinski, Kirsten B Andersen, I Sadaf Farooqi, Daniel Sejer Pedersen, David E Gloriam, Hans Bräuner-Osborne
GPR139 is an orphan G protein-coupled receptor that is expressed primarily in the brain. Not much is known regarding the function of GPR139. Recently we have shown that GPR139 is activated by the amino acids l-tryptophan and l-phenylalanine (EC50 values of 220 μM and 320 μM, respectively), as well as di-peptides comprised of aromatic amino acids. This led us to hypothesize that GPR139 may be activated by peptides. Sequence alignment of the binding cavities of all class A GPCRs, revealed that the binding pocket of the melanocortin 4 receptor is similar to that of GPR139...
January 2017: Neurochemistry International
https://www.readbyqxmd.com/read/27914477/in-vitro-rescue-of-genital-strains-of-chlamydia-trachomatis-from-interferon-%C3%AE-and-tryptophan-depletion-with-indole-positive-but-not-indole-negative-prevotella-spp
#17
Noa Ziklo, Wilhelmina M Huston, Kuong Taing, Mohammad Katouli, Peter Timms
BACKGROUND: The natural course of sexually transmitted infections caused by Chlamydia trachomatis varies between individuals. In addition to parasite and host effects, the vaginal microbiota might play a key role in the outcome of C. trachomatis infections. Interferon-gamma (IFN-γ), known for its anti-chlamydial properties, activates the expression of indoleamine 2,3-dioxygenase (IDO1) in epithelial cells, an enzyme that catabolizes the amino acid L- tryptophan into N-formylkynurenine, depleting the host cell's pool of tryptophan...
December 3, 2016: BMC Microbiology
https://www.readbyqxmd.com/read/27909574/characterization-of-5-2-18-f-fluoroethoxy-l-tryptophan-for-pet-imaging-of-the-pancreas
#18
Ahmed Abbas, Christine Beamish, Rebecca McGirr, John Demarco, Neil Cockburn, Dawid Krokowski, Ting-Yim Lee, Michael Kovacs, Maria Hatzoglou, Savita Dhanvantari
Purpose: In diabetes, pancreatic beta cell mass declines significantly prior to onset of fasting hyperglycemia. This decline may be due to endoplasmic reticulum (ER) stress, and the system L amino acid transporter LAT1 may be a biomarker of this process. In this study, we used 5-(2- (18)F-fluoroethoxy)-L-tryptophan ( (18)F-L-FEHTP) to target LAT1 as a potential biomarker of beta cell function in diabetes. Procedures: Uptake of (18)F-L-FEHTP was determined in wild-type C57BL/6 mice by ex vivo biodistribution...
2016: F1000Research
https://www.readbyqxmd.com/read/27889626/absence-of-kynurenine-3-monooxygenase-reduces-mortality-of-acute-viral-myocarditis-in-mice
#19
Hisako Kubo, Masato Hoshi, Akihiro Mouri, Chieko Tashita, Yasuko Yamamoto, Toshitaka Nabeshima, Kuniaki Saito
Infection of the encephalomyocarditis virus (EMCV) in mice is an established model for viral myocarditis. Previously, we have demonstrated that indoleamine 2,3-dioxygenase (IDO), an L-tryptophan - kynurenine pathway (KP) enzyme, affects acute viral myocarditis. However, the roles of KP metabolites in EMCV infection remain unclear. Kynurenine 3-monooxygenase (KMO) is one of the key regulatory enzymes, which metabolizes kynurenine to 3-hydroxykynurenine in the KP. Therefore, we examined the role of KMO in acute viral infection by comparing between KMO(-/-) mice and KMO(+/+) mice...
November 24, 2016: Immunology Letters
https://www.readbyqxmd.com/read/27889579/protective-effects-of-high-tryptophan-diet-on-aging-induced-passive-avoidance-impairment-and-hippocampal-apoptosis
#20
Giuseppe Musumeci, Paola Castrogiovanni, Marta Anna Szychlinska, Rosa Imbesi, Carla Loreto, Sergio Castorina, Salvatore Giunta
In our previous work we have shown that L-Tryptophan (TrP) enriched diet prevents the age-induced decline of hippocampal Serotonin (5-HT) production. Considering that loss or reduction in 5-HT neurotransmission may contribute to age-related cognitive decline, here we have investigated the effect of such diet on passive avoidance (PA) behavior, cell death, pro- and anti- apoptotic molecules (BAX, Bcl-2 and Caspase-3) and an important transcription factor involved in synaptic plasticity and memory (CREB). The increase in 5-HT neurotransmission in the Hippocampus (Hp) of aged rats was induced by 1 month of high TrP administration...
January 2017: Brain Research Bulletin
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