Chemical properties of 3-substituted pyridine analogues of diphosphopyridine nucleotide.

It has been shown previously that the diphosphopyridine nucleotidase from pig brain is capable of catalyzing an exchange reaction between various substituted pyridine compounds and diphosphopyridine nucleotide to form analogues of diphosphopyridine nucleotide (l-4). The variation in reactivity of the various analogues prepared in this manner indicates the importance of the grouping in position 3 of the pyridine moiety of the molecule. Analogues containing pyridine, /3-picoline or 3methylpyridylcarbinol cannot be reduced either chemically or enzymatically and do not react in the various addition reactions characteristic of diphosphopyridine nucleotide (2). On the other hand, analogues containing 3-acetylpyridine or pyridine-3-aldehyde will undergo chemical and enzymatic reduction and react to form addition products. This paper constitutes an extension of these studies to include other pyridine-substituted analogues of diphosphopyridine nucleotide. Data will be presented to demonstrate the variation in properties of pyridine dinucleotide compounds differing from diphosphopyridine nucleotide by the nature of the group in position 3 of the pyridine moiety. Preliminary studies involving these compounds were recently reported (5).