Determination of the hydride transfer stereospecificity of nicotinamide adenine dinucleotide linked oxidoreductases by proton magnetic resonance

Abstract

A facile PMR technique is described for the determination of the coenzyme stereospecificity during hydride transfer reactions catalyzed by pyridine nucleotide dependent oxidoreductases. The reliability of this technique was demonstrated by examining the coenzyme stereospecificity of lactate, malate and 3-phosphoglycerate dehydrogenases, which are known to be A-stereospecific enzymes, as well as triosephosphate and octopine dehydrogenases, which are known to be B-stereospecific enzymes. By applying this technique it was shown that the previously unstudied enzymes D-.beta.-hydroxybutyrate and 4-aminobutanal dehydrogenases [bovine heart and Pseudomonas, respectively] are B- and A-stereospecific enzymes, respectively. The NAD linked reaction of G-6-P dehydrogenase from Leuconostoc mesenteroides is B stereospecific, like the reaction of the NADP linked yeast enzyme.