In vitro oxidative decarboxylation of L-2-hydroxy-4-methylthiobutanoic acid by L-2-hydroxy acid oxidase A from chicken liver

Autor: Anne Ferjancic-Biagini, J. De Caro, Liliane Dupuis, Antoine Puigserver
Rok vydání: 1995
Předmět:
Zdroj: Biochimie. 77:249-255
ISSN: 0300-9084
DOI: 10.1016/0300-9084(96)88132-6
Popis: The first step in the set of reactions responsible for the biological utilization of L-2-hydroxy-4-methylthiobutanoic acid, the methionine hydroxy analogue, in protein synthesis was investigated in vitro using pure L-2-hydroxy acid oxidase A from chicken liver. The reaction yielded no more than 20% of the corresponding α-keto acid, 2-keto-4-methylthiobutanoic acid, the well-known intermediate in methionine metabolism, and as much as 80% of the subsequent decarboxylation product, 3-methylthiopropionate, suggesting that L-2-hydroxy-4-methylthiobutanoic acid cannot be completely converted into methionine in vivo . It was therefore concluded that chicken liver L-2-hydroxy acid oxidase, a peroxisomal enzyme requiring flavin mononucleotide as a coenzyme, also has an oxidative decarboxylation activity in vitro , which was found to be NADH-dependent. The mechanism possibly underlying the successive conversion of the methionine hydroxy analogue into α-keto acid and 3-methylthiopropionate by this NADH:flavin oxido-reductase-decarboxylase activity is described.
Databáze: OpenAIRE
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