98-79-3Relevant articles and documents
Identification and characterization of γ-glutamylamine cyclotransferase, an enzyme responsible for γ-glutamyl-ε-lysine catabolism
Oakley, Aaron J.,Coggan, Marjorie,Board, Philip G.
, p. 9642 - 9648 (2010)
γ-Glutamylamine cyclotransferase (GGACT) is an enzyme that converts γ-glutamylamines to free amines and 5-oxoproline. GGACT shows high activity toward γ-glutamyl-ε-lysine, derived from the breakdown of fibrin and other proteins cross-linked by transglutaminases. The enzyme adopts the newly identified cyclotransferase fold, observed in γ- glutamylcyclotransferase (GGCT), an enzyme with activity toward γ-glutamyl-α-amino acids (Oakley, A. J., Yamada, T., Liu, D., Coggan, M., Clark, A. G., and Board, P. G. (2008) J. Biol. Chem. 283, 22031-22042). Despite the absence of significant sequence identity, several residues are conserved in the active sites of GGCTand GGACT, including a putative catalytic acid/base residue (GGACT Glu82). The structure of GGACT in complex with the reaction product 5-oxoproline provides evidence for a commoncatalytic mechanism in both enzymes. The proposed mechanism, combined with the three-dimensional structures, also explains the different substrate specificities of these enzymes. Despite significant sequence divergence, there are at least three subfamilies in prokaryotes and eukaryotes that have conserved the GGCT fold and GGCT enzymatic activity.
Massive Glutamine Cyclization to Pyroglutamic Acid in Human Serum Discovered Using NMR Spectroscopy
Gowda, G. A. Nagana,Gowda, Yashas N.,Raftery, Daniel
, p. 3800 - 3805 (2015)
Glutamine is one of the most abundant metabolites in blood and is a precursor as well as end product central to numerous important metabolic pathways. A number of surprising and unexpected roles for glutamine, including cancer cell glutamine addiction discovered recently, stress the importance of accurate analysis of glutamine concentrations for understanding its role in health and numerous diseases. Utilizing a recently developed NMR approach that offers access to an unprecedented number of quantifiable blood metabolites, we have identified a surprising glutamine cyclization to pyroglutamic acid that occurs during protein removal. Intact, ultrafiltered and protein precipitated samples from the same pool of human serum were comprehensively investigated using 1H NMR spectroscopy at 800 MHz to detect and quantitatively evaluate the phenomenon. Interestingly, although glutamine cyclization occurs in both ultrafiltered and protein precipitated serum, the cyclization was not detected in intact serum. Strikingly, due to cyclization, the apparent serum glutamine level drops by up to 75% and, concomitantly, the pyroglutamic acid level increases proportionately. Further, virtually under identical conditions, the magnitude of cyclization is vastly different for different portions of samples from the same pool of human serum. However, the sum of glutamine and pyroglutamic acid concentrations in each sample remains the same for all portions. These unexpected findings indicate the importance of considering the sum of apparent glutamine and pyroglutamic acid levels, obtained from the contemporary analytical methods, as the actual blood glutamine level for biomarker discovery and biological interpretations. (Graph Presented)
Crystal structure and functional analysis of the glutaminyl cyclase from Xanthomonas campestris
Huang, Wei-Lin,Wang, Yu-Ruei,Ko, Tzu-Ping,Chia, Cho-Yun,Huang, Kai-Fa,Wang, Andrew H.-J.
, p. 374 - 388 (2010)
Glutaminyl cyclases (QCs) (EC 2.3.2.5) catalyze the formation of pyroglutamate (pGlu) at the N-terminus of many proteins and peptides, a critical step for the maturation of these bioactive molecules. Proteins having QC activity have been identified in animals and plants, but not in bacteria. Here, we report the first bacterial QC from the plant pathogen Xanthomonas campestris (Xc). The crystal structure of the enzyme was solved and refined to 1.44-A resolution. The structure shows a β-propeller and exhibits a scaffold similar to that of papaya QC (pQC), but with some sequence deletions and conformational changes. In contrast to the pQC structure, the active site of XcQC has a wider substrate-binding pocket, but its accessibility is modulated by a protruding loop acting as a flap. Enzyme activity analyses showed that the wild-type XcQC possesses only 3% QC activity compared to that of pQC. Superposition of those two structures revealed that an active-site glutamine residue in pQC is substituted by a glutamate (Glu45) in XcQC, although position 45 is a glutamine in most bacterial QC sequences. The E45Q mutation increased the QC activity by an order of magnitude, but the mutation E45A led to a drop in the enzyme activity, indicating the critical catalytic role of this residue. Further mutagenesis studies support the catalytic role of Glu89 as proposed previously and confirm the importance of several conserved amino acids around the substrate-binding pocket. XcQC was shown to be weakly resistant to guanidine hydrochloride, extreme pH, and heat denaturations, in contrast to the extremely high stability of pQC, despite their similar scaffold. On the basis of structure comparison, the low stability of XcQC may be attributed to the absence of both a disulfide linkage and some hydrogen bonds in the closure of β-propeller structure. These results significantly improve our understanding of the catalytic mechanism and extreme stability of type I QCs, which will be useful in further applications of QC enzymes.
Preparation method of (S)-1 - (benzyloxycarbonyl) -5 -oxo-pyrrolidine -2 - formic acid
-
Paragraph 0044, (2021/09/01)
The invention discloses a preparation method of (S)-1 - (benzyloxycarbonyl) -5 -oxo-pyrrolidine -2 - formic acid, which mainly solves the complexity in the original process, and is long in period and high in cost. The method specifically comprises first steps of preparing L - benzyloxycarbonyl N - glutamic acid from - L - glutamic acid and a benzyloxycarbonyl donor, second steps of intramolecular condensation cyclization N - benzyloxycarbonyl - L - glutamic acid to obtain the N -benzyloxycarbonyl - L - glutamic acid crude product. The third The crude N - benzyloxycarbonyl - L - glutamic acid crude product and the organic amine base are mixed, and the organic amine salt form is prepared by the solubility of the product in a solvent, fourth (N -) - L - (benzyloxycarbonyl) S oxopyrrolidine -1 - formic acid is prepared by desalinating -5 - benzyloxycarbonyl -2 - glutamic acid. To the method, the high-purity product is prepared, and the yield and the quality are greatly improved.
A colorimetric assay method for measuring D-glutamate cyclase activity
Ariyoshi, Makoto,Hamase, Kenji,Homma, Hiroshi,Katane, Masumi,Matoba, Satoaki,Mita, Masashi,Miyamoto, Tetsuya,Motoda, Risa,Nakayama, Kazuki,Saitoh, Yasuaki,Sakai-Kato, Kumiko,Sekine, Masae,Tateishi, Shuhei
, (2020/07/31)
In mammals, metabolism of free D-glutamate is regulated by D-glutamate cyclase (DGLUCY), which reversibly converts D-glutamate to 5-oxo-D-proline and H2O. Metabolism of these D-amino acids by DGLUCY is thought to regulate cardiac function. In this study, we established a simple, accurate, and sensitive colorimetric assay method for measuring DGLUCY activity. To this end, we optimized experimental procedures for derivatizing 5-oxo-D-proline with 2-nitrophenylhydrazine hydrochloride. 5-Oxo-D-proline was derivatized with 2-nitrophenylhydrazine hydrochloride in the presence of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide as a catalyst to generate the acid hydrazides, whose levels were then determined using a colorimetric method. Under optimized conditions, we examined the sensitivity and accuracy of the colorimetric method and compared our technique with other methods by high-performance liquid chromatography with ultraviolet–visible or fluorescence detection. Moreover, we assessed the suitability of this colorimetric method for measuring DGLUCY activity in biological samples. Our colorimetric method could determine DGLUCY activity with adequate validity and reliability. This method will help to elucidate the relationship among DGLUCY activity, the physiological and pathological roles of D-glutamate and 5-oxo-D-proline, and cardiac function.
Designed proteinoid polymers and nanoparticles encapsulating risperidone for enhanced antipsychotic activity
Einat, H.,Grinberg, I.,Lugasi, L.,Margel, S.,Okun, E.,Rudnick-Glick, S.
, (2020/10/28)
Background: Nanoparticles (NPs) incorporating drug formulations can be used to facilitate passage through biological barriers including the blood–brain barrier (BBB) and increase drug delivery and bioavailability. Hence, NP-based administration may enhance the efficiency of current antipsychotics. Encapsulation within NPs can resolve aqueous solubility problems that not only reduce permeability through the BBB but also affect targeting. The present study describes a new drug delivery system based on proteinoid NPs to explore the possibility of improving drug efficacy. Risperidone (RSP) is a commonly used atypical antipsychotic medication, and was therefore selected for encapsulation by proteinoid NPs. Results: Proteinoid polymers with high molecular weight and low polydispersity were synthesized from l-amino acids and poly-l-lactic acid (PLLA) by thermal step-growth polymerization mechanism. RSP-loaded proteinoid NPs were then prepared using a self-assembly process in the presence of RSP, followed by PEGylation. The optimal PEGylated RSP-loaded NPs were characterized in terms of diameter and size distribution, drug loading, ζ-potential, cytotoxicity, biodistribution, and psychopharmacological effects. The findings indicate significantly higher antipsychotic activity of drug-loaded proteinoid NPs compared to free RSP. Conclusions: Proteinoid NPs enhance RSP delivery and may potentially increase drug efficiency by reducing dosage and side effects.[Figure not available: see fulltext.].
Organocatalytic Decarboxylation of Amino Acids as a Route to Bio-based Amines and Amides
Claes, Laurens,Janssen, Michiel,De Vos, Dirk E.
, p. 4297 - 4306 (2019/08/26)
Amino acids obtained by fermentation or recovered from protein waste hydrolysates represent an excellent renewable resource for the production of bio-based chemicals. In an attempt to recycle both carbon and nitrogen, we report here on a chemocatalytic, metal-free approach for decarboxylation of amino acids, thereby providing a direct access to primary amines. In the presence of a carbonyl compound the amino acid is temporarily trapped into a Schiff base, from which the elimination of CO2 may proceed more easily. After evaluating different types of aldehydes and ketones on their activity at low catalyst loadings (≤5 mol%), isophorone was identified as powerful organocatalyst under mild conditions. After optimisation many amino acids with a neutral side chain were converted in 28–99 % yield in 2-propanol at 150 °C. When the reaction is performed in DMF, the amine is susceptible to N-formylation. This consecutive reaction is catalysed by the acidity of the amino acid reactant itself. In this way, many amino acids were efficiently transformed to the corresponding formamides in a one-pot catalytic system.
Substrate Specificity and Chemical Mechanism for the Reaction Catalyzed by Glutamine Kinase
Taylor, Zane W.,Chamberlain, Alexandra R.,Raushel, Frank M.
, (2018/09/21)
Campylobacter jejuni, a leading cause of gastroenteritis worldwide, has a unique O-methyl phosphoramidate (MeOPN) moiety attached to its capsular polysaccharide. Investigations into the biological role of MeOPN have revealed that it contributes to the pathogenicity of C. jejuni, and this modification is important for the colonization of C. jejuni. Previously, the reactions catalyzed by four enzymes (Cj1418-Cj1415) from C. jejuni that are required for the biosynthesis of the phosphoramidate modification have been elucidated. Cj1418 (l-glutamine kinase) catalyzes the formation of the initial phosphoramidate bond with the ATP-dependent phosphorylation of the amide nitrogen of l-glutamine. Here we show that Cj1418 catalyzes the phosphorylation of l-glutamine through a three-step reaction mechanism via the formation of covalent pyrophosphorylated (Enz-X-Pβ-Pγ) and phosphorylated (Enz-X-Pβ) intermediates. In the absence of l-glutamine, the enzyme was shown to catalyze a positional isotope exchange (PIX) reaction within β-[18O4]-ATP in support of the formation of the Enz-X-Pβ-Pγintermediate. In the absence of ATP, the enzyme was shown to catalyze a molecular isotope exchange (MIX) reaction between l-glutamine phosphate and [15N-amide]-l-glutamine in direct support of the Enz-X-Pβintermediate. The active site nucleophile has been identified as His-737 based on the lack of activity of the H737N mutant and amino acid sequence comparisons. The enzyme was shown to also catalyze the phosphorylation of d-glutamine, γ-l-glutamyl hydroxamate, γ-l-glutamyl hydrazide, and β-l-aspartyl hydroxamate, in addition to l-glutamine.
Substrate Specificity and Chemical Mechanism for the Reaction Catalyzed by Glutamine Kinase
Taylor, Zane W.,Chamberlain, Alexandra R.,Raushel, Frank M.
, p. 5447 - 5455 (2018/09/25)
Campylobacter jejuni, a leading cause of gastroenteritis worldwide, has a unique O-methyl phosphoramidate (MeOPN) moiety attached to its capsular polysaccharide. Investigations into the biological role of MeOPN have revealed that it contributes to the pathogenicity of C. jejuni, and this modification is important for the colonization of C. jejuni. Previously, the reactions catalyzed by four enzymes (Cj1418-Cj1415) from C. jejuni that are required for the biosynthesis of the phosphoramidate modification have been elucidated. Cj1418 (l-glutamine kinase) catalyzes the formation of the initial phosphoramidate bond with the ATP-dependent phosphorylation of the amide nitrogen of l-glutamine. Here we show that Cj1418 catalyzes the phosphorylation of l-glutamine through a three-step reaction mechanism via the formation of covalent pyrophosphorylated (Enz-X-Pβ-Pγ) and phosphorylated (Enz-X-Pβ) intermediates. In the absence of l-glutamine, the enzyme was shown to catalyze a positional isotope exchange (PIX) reaction within β-[18O4]-ATP in support of the formation of the Enz-X-Pβ-Pγintermediate. In the absence of ATP, the enzyme was shown to catalyze a molecular isotope exchange (MIX) reaction between l-glutamine phosphate and [15N-amide]-l-glutamine in direct support of the Enz-X-Pβintermediate. The active site nucleophile has been identified as His-737 based on the lack of activity of the H737N mutant and amino acid sequence comparisons. The enzyme was shown to also catalyze the phosphorylation of d-glutamine, γ-l-glutamyl hydroxamate, γ-l-glutamyl hydrazide, and β-l-aspartyl hydroxamate, in addition to l-glutamine.
Method for preparing hydrobromic acid teneligliptin
-
Paragraph 0043; 0044, (2017/07/01)
The invention provides a method for preparing hydrobromic acid teneligliptin. The method includes steps of preparing L-hydroxyproline; mixing the L-hydroxyproline and sodium bicarbonate with each other to obtain mixtures, dissolving the mixtures in water, adding acetone into the water, dropping di-tert-butyl dicarbonate into the water, carrying out room-temperature reaction overnight and then treating reaction products to obtain t-butyloxycarboryl-N-hydroxyproline; preparing t-butyloxycarboryl-N-4-oxo-proline from the t-butyloxycarboryl-N-hydroxyproline; preparing (2S)-4-oxo-2-(3-thiazolidine carbonyl)-1-pyrrolidine carboxylic acid tert-butyl ester from the t-butyloxycarboryl-N-4-oxo-proline; preparing compounds III from compounds IV; preparing compounds II from the compounds III; preparing compounds 1-(3-methyl-1-phenyl-1H-pyrazole-5-base) piperazine from the compounds II; preparing intermediates I; preparing the hydrobromic acid teneligliptin from the intermediates I. The method has the advantages that the method is low in cost, and the cost of the method is only two-thirds of the cost of an existing method in the prior art; the yield of the hydrobromic acid teneligliptin is higher than 95%, and the purity of the hydrobromic acid teneligliptin is higher than 98%.
