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

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

The fate of nitrogen originating from the amide group of asparagine in young pea leaves (Pisum sativum) has been studied by supplying [(15)N-amide]asparagine and its metabolic product, 2-hydroxysuccinamate (HSA) via the transpiration stream. Amide nitrogen from asparagine accumulated predominantly in the amide group of glutamine and HSA, and to a lesser extent in glutamate and a range of other amino acids. Treatment with 5-diazo,4-oxo-L-norvaline (DONV) a deamidase inhibitor, caused a decrease in transfer of label to glutamine-amide. Virtually no (15)N was detected in HSA of leaves supplied with asparagine and the transaminase inhibitor aminooxyacetate. When [(15)N]HSA was supplied to pea leaves, most of the label was also found in the amide group of glutamine and this transfer was blocked by the addition of methionine sulfoximine, which caused a large increase in NH(3) accumulation. DONV was not specific for asparaginase, and inhibited the deamidation of HSA, causing a decrease in transfer of (15)N into glutamine-amide, NH(3), and other amino acids. It is concluded from these results that use of the amide group of asparagine as a nitrogen source for young pea leaves involves deamidation of both asparagine and its transamination product HSA (possibly also oxosuccinamate). The amide group, released as ammonia, is then reassimilated via the glutamine synthetase/glutamate synthase system.
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PMID:Utilization of the amide groups of asparagine and 2-hydroxysuccinamic Acid by young pea leaves. 1666 59


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