Absence of direct coenzyme transfer in an A-B dehydrogenase system.
Direct transfer of NADPH between two NADP-dependent dehydrogenases, isocitrate dehydrogenase and glutamate dehydrogenase, has been investigated. These enzymes have opposite stereospecificity for hydrogen transfer to the coenzyme. In contrast with the general direct-transfer mechanism postulated for NAD-dependent dehydrogenases [Srivastava & Bernhard (1986) Science 234, 1081-1086], no evidence for direct transfer in either direction was found for these NADP-dependent dehydrogenases.
Department of Chemistry and Biochemistry, University of Delaware, Newark 19716.
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D005969:Glutamate Dehydrogenase / Q000378:metabolism*; D007521:Isocitrate Dehydrogenase / Q000378:metabolism*; D007656:Ketoglutaric Acids / Q000378:metabolism; D007700:Kinetics; D009249:NADP / Q000378:metabolism*; D010084:Oxidation-Reduction
D007656:Ketoglutaric Acids; D009249:NADP; D007521:Isocitrate Dehydrogenase; D005969:Glutamate Dehydrogenase