Natural Occurrence and Enzymatic Synthesis of a=Nicotinamide Adenine Dinucleotide Phosphate*

A pyridine nucleotide has been synthesized from cr-nicotinamide adenine dinucleotide and adenosine triphosphate with the use of a crude enzyme preparation from Azotobacfer uinelandii strain 0. Evidence is presented that this nucleotide is the (Y isomer of NADP, ar-NADP, which differs from &NADP in the configuration of the nicotinamide-ribosidic linkage. This evidence rests on a study of (a) spectral properties, (b) degradation by snake venom phosphodiesterase followed by comparison with authentic samples, (c) stability of the nicotinamide-ribonucleosidic linkage in acid, and (d) optical rotatory dispersion. In contrast to P-NADP, ar-NADP is not active with yeast glucose 6-phosphate dehydrogenase, nor is it cleaved by Neurospora crassa NAD glycohydrolase. o-NADP has been shown to be present in the cells of A. vinelandii; about 1: 10 has been found for a normal equilibrium molar ratio of a-NADP to /3-NADP.