Octopine dehydrogenase from crown gall tumor and from Pecten maximus. Oxidation of (4R)- and (4S)-[4-3H]NADH.
The stereospecificity of octopine dehydrogenase from crown gall tumor and of octopine dehydrogenase from scallops (Pecten maximum) with respect to the oxidation of C-4 of the dihydronicotinamide ring of NADH was investigated by determination of the distribution of radioactivity after oxidation of (4R)- and (4S)-[4-3H]NADH. Octopine dehydrogenase from crown gall tumor and from scallops stereospecifically removes the pro-S hydrogen atom of the dihydronicotinamide ring with transfer of label to the solvent and to the product octopine (N-2-(1-carboxyethyl)-L-arginine). Although to a lesser extent, the exchange of label from (4S)-[4-3H]NADH with solvent was found to occur when octopine dehydrogenase from either crown gall tumor or from scallops was incubated in the absence of other substrates. Possible mechanisms to explain this exchange are discussed.
D000594:Amino Acid Oxidoreductases / Q000378:metabolism*; D000818:Animals; D008956:Models, Chemical; D008974:Mollusca / Q000201:enzymology*; D009243:NAD / Q000378:metabolism*; D010084:Oxidation-Reduction; D010941:Plant Tumors / Q000201:enzymology*
D009243:NAD; D000594:Amino Acid Oxidoreductases; C021903:D-octopine dehydrogenase