Preparation and properties of 3-halopyridine--adenine dinucleotides, NAD+ analogues and model compounds.

The preparation of model compounds 1-(2',6'-dichlorobenzyl)-3-halogenopyridinium and the study of their properties were achieved. Their chemical reduction to the corresponding 1,4-dihydropyridines is proved by spectroscopic analysis. 3-Iodopyridine--adenine dinucleotide was prepared by enzymic transglycosidation while the 3-chloro, 3-bromo and 3-iodo pyridine--adenine dinucleotides were synthesized from 3-amino-pyridine--adenine dinucleotide. The 3-halogenopyridine--adenine dinucleotides were proved to be active as hydrogen acceptors with alcohol as a substrate. The absorption band at 290 nm of cinnamaldehyde appeared to be a very sensitive tool for studying the enzymic reaction. With the alcohol dehydrogenase from yeast, only slight activity was detected. 3-Halogenopyridine--adenine dinucleotides are competitive inhibitors with respect to nicotinamide--adenine dinucleotide with alcohol dehydrogenase from yeast, lactate dehydrogenase and malate dehydrogenase. The use of 3-iodopyridine--adenine dinucleotide as a heavy-atom derivative for X-ray structure determination is proposed.