[Hydrosoluble polymers of NAD+ and ADP. Study of their coenzymatic properties as a function of their size]

Hydrosoluble polymers of NAD+ and ADP were synthesized according to a described method with some modifications. The cofactor was bound to the matrix by a spacer group of five atoms at the exocyclic adenine C-6 amino group. Cofactor incorporations were very high. The loading of NAD+ polymers were: 420 mumol NAD+/g polymer and 330 mumol ADP ribose/g polymer arising from degradation of NAD+; the loading of ADP polymers were: 1.40 and 1.43 mmol ADP/g polymer. Each polymer obtained in a same polymerization step was fractionated in two parts by gel filtration in such a manner that these two parts had the same framework but different molecular weights. The biological properties of the fractionated polymers were compared. The small sized polymers of NAD+, assayed with four dehydrogenases, were more reduced enzymatically than the larger ones and had the higher reduction rates relative to free NAD+. In a coupled system (L-lactate dehydrogenase, formate dehydrogenase) with coenzyme regeneration, the rate of production of L-lactate at the steady state of the system using NAD+ polymers of small size was 80% that of the system using free NAD+. The small-sized polymers of ADP were more phosphorylated by pyruvate kinase and creatine kinase than the larger ones. But the relative rates of transformation by pyruvate kinase of large sized polymers were higher than those of smaller ones.