Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.1 (asparaginase)
 2,695 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A method for determination of the transferase activity of 1-asparaginase in presence of hydroxylamine is developed. The optimally determined quantity of the enzyme was from 0.7 to 20 i. u. The conditions optimal for the enzymatic reaction and for quantitative estimation of 1-aspartyl-beta-hydroxamic acid were studied. The transferase and hydrolase activities of 1-asparaginase from E. coli were compared. The enzyme catalyzed at equal rates hydrolysis and hydroxylaminolysis of 1-asparagine.
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PMID:[Determination of the transferase activity of L-asparaginase]. 0 24

Crude extracts of BCG, M. fortuitum and M. phlei, hydrolyse asparagine (I) and L-beta-asparthohydroxamic acid (III), and catalyse the synthesis of aspartohydroxamic acid from asparagine and hydroxylamine (II). The ratio between these enzymatic activities (I:II and I:III) presents a certain stability during the different steps of purification of these mycobacteria asparaginases. In particular, M. fortuitum asparaginase has been purified 90 to 130-fold, with recovery of approximately 10%. Only the fractions of supernatants which have an asparaginase activity catalyse the formation of aspartohydroxamate from asparagine and hydroxylamine. Some differences between the asparaginases of these strains are described. Particularaly, in comparison to reaction I, their abilities to catalyse reactions II and III vary noticeably from one asparaginase to an other. The asparaginase of BCG catalyses very slightly in the reactions II and III and is more specific of L-asparagine hydrolysis than are the asparaginases of M. fortuitum and of M. phlei. Furthermore, in the case of M. phlei, p-chloromercuribenzoate (pCMB) inhibits very stronly the reactions I and III and slightly reaction II, whereas conversely, for M. fortuitum, pCMB does not inhibit reactions I and III but strongly inhibits reaction II. In the case of BCG, these three reactions are not inhibited by pCMB. Moreover, the asparaginases from these strains are more or less sensitive to the ionic strength of the buffer used.
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PMID:[Asparagine metabolism in mycobacteria. II. -- Asparagine hydrolysis and aspartohydroxamic acid formation and hydrolysis catalysed by M. fortuitum, M. phlei and BCG asparaginases (author's transl)]. 23 19

Among studied 40 bacterial cultures, 17 strains catalysed hydroxylaminolysis of I.-asparagine and L-glutamine, and among these cultures seven strains belonged to the Pseudomonas genus. Extracts of the cells of Ps. boreopolis 526 (MGU), Ps. aurantiaca IBFM B-14, and Ps. septica IBFM B-40 had the maximum deamidase activity during the stage of decelerated growth. The activity of L-asparaginase 2 was practically the same upon various ways of disintegration of the cells of Ps. aurantiaca IBFM B-14: ballistic technique, ultrasound, extrusion form the solid state. Production of beta-aspartylhydroxamic acid by L-asparaginase 2 depended on the concentration of hydroxylamine and protein in the reaction mixture and on the duration of the reaction.
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PMID:[Formation of L-asparagine and L-glutamine deamidases by bacterial cultures]. 78 74

Human glycoasparaginase (N4-(beta-N-acetyl-D-glucosaminyl)-L-asparaginase, EC 3.5.1.26) hydrolyzes a series of compounds that contain L-asparagine residue with free alpha-amino and alpha-carboxyl groups. Substrates include high mannose and complex type glycoasparagines as well as those that lack the di-N-acetylchitobiose moiety, L-aspartic acid beta-methyl ester and L-aspartic acid beta-hydroxamate. The enzyme is inactive toward L-asparagine and L-glutamine and glycoasparagines containing substituted alpha-amino and/or alpha-carboxyl groups. In the presence of the acyl acceptor hydroxylamine, glycoasparaginase catalyzes the synthesis of L-aspartic acid beta-hydroxamate from aspartyl-glucosamine, L-aspartic acid beta-methyl ester, and L-aspartic acid. 13C NMR studies using 18O-labeled L-aspartic acid demonstrate that glycoasparaginase catalyzes an oxygen exchange between water and the carboxyl group at C-4 of L-aspartic acid. These results indicate that glycoasparaginase reacts as an exo-hydrolase toward the L-asparagine moiety of the substrates and the free alpha-amino and alpha-carboxyl groups are required for the enzyme reaction. The results are consistent with an L-asparaginase-like reaction pathway which involves a beta-aspartyl enzyme intermediate. Since glycoasparaginase is active toward a series of structurally different glycoasparagines, we suggest the revised systematic name of N4-(beta-glycosyl)-L-asparaginase for the enzyme.
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PMID:Substrate specificity and reaction mechanism of human glycoasparaginase. The N-glycosidic linkage of various glycoasparagines is cleaved through a reaction mechanism similar to L-asparaginase. 155 92

The enzyme L-asparaginase (ASNASE), which hydrolyzes L-asparagine (L-Asn) to ammonia and L-aspartic acid (L-Asp), is commonly used for remission induction in acute lymphoblastic leukemia. To correlate ASNASE activity with L-Asn reduction in human serum, sensitive methods for the determination of ASNASE activity are required. Using L-aspartic beta-hydroxamate (AHA) as substrate we developed a sensitive plate reader-based method for the quantification of ASNASE derived from Escherichia coli and Erwinia chrysanthemi and of pegylated E. coli ASNASE in human serum. ASNASE hydrolyzed AHA to L-Asp and hydroxylamine, which was determined at 710 nm after condensation with 8-hydroxyquinoline and oxidation to indooxine. Measuring the indooxine formation allowed the detection of 2 x 10(-5)U ASNASE in 20 microl serum. Linearity was observed within 2.5-75 and 75-1,250 U/L with coefficients of correlation of r(2)>0.99. The coefficients of variation for intra- and interday variability for the three different ASNASE enzymes were 1.98 to 8.77 and 1.73 to 11.0%. The overall recovery was 101+/-9.92%. The coefficient of correlation for dilution linearity was determined as r(2)=0.986 for dilutions up to 1:20. This method combined with sensitive methods for the quantification of L-Asn will allow bioequivalence studies and individualized therapeutic drug monitoring of different ASNASE preparations.
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PMID:Analytical validation of a microplate reader-based method for the therapeutic drug monitoring of L-asparaginase in human serum. 1238 70

The asparagine analog, 5-diazo-4-oxo-L-norvaline is a substrate and an irreversible inhibitor of L-asparaginase. Covalent attachment occurs at an increased rate at concentrations of dimethylsulfoxide which reduce the catalytic decomposition of diazo-oxo-norvaline. In 55% dimethylsulfoxide asparaginase is inactivated by diazo-oxo-norvaline (0.05 M) with a t 1/2 of twelve seconds. In aqueous buffer the rate of diazo-oxo-norvaline decomposition is increased three-fold in the presence of the nucleophile hydroxylamine; this nucleophile also protects the enzyme against inactivation by diazo-oxo-norvaline in the presence of dimethylsulfoxide.
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PMID:The active site of L-asparaginase: dimethylsulfoxide effect of 5-diazo-4-oxo-L-norvaline interactions. 1562 86