[Immobilization of nicotine amide adenine dinucleotide derivatives and their function as cofactors of bacterial formic dehydrogenase]

NAD+ was modified with respect to the C(6)-amino group of the adenine residue by iod acetic acid alkylation in N1-position and subsequent rearrangement into N6-position. By condensation of N6-carboxy methyl-NAD+ with 1,6-diamino hexane, N6-[(6-aminohexyl)-acetamide]-NAD+ was synthesized. This process was controlled spectrophotometrically and by analytical isotachophoresis. NAD+ derivatives were found to maintain high co-enzymic activity in the reaction of formic oxidation with formic dehydrogenase from gram-negative methylotrophic bacteria, str. 1. Kinetic parameters of the reaction involving the resultant components were determined. NAD+N6-derivatives were covalently bound with the water insoluble carrier--Sepharose 4B and water soluble carriers--acrolein and 4-vinyl pyridine copolymers and dextran. The rates of formic dehydrogenase reduction of the native and immobilized cofactors were compared.