Stereochemistry of enzyme-catalyzed reactions at carbon

NADH. These experiments were pioneering with respect to contemporary enzymology, especially with regard to early recognition that coenzymes are held within enzyme active sites in stereochemically preferred ways. One typically utilizes NADH that contains a tritium or deuterium atom in the 4R or 45 position, and the success or failure of substrate deuteration/tritiation indicates the stereochemistry. Westheimer has tabulated the known examples of dehydrogenases that exhibit specificity for a particular face of NADH. Creighton and Murthy have reproduced this tabulation in their comprehensive review on the stereochemistry of enzyme-catalyzed reactions at carbon. 

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