Biopolymers and cell. 1987. Volume 3. № 6. 327 - 329

R. R. Petrov, I. B. Utkin, A. M. Egorov, V. O. Popov

THE EFFECT OF REDOX POTENTIAL OF THE MEDIUM ON THE CATALYTIC ACTIVITY OF NAD-DEPENDENT HYDROGENASE

Summary

    The effect of redox potential of the medium on the catalytic properties of soluble hydrogenase from hydrogen-oxidizing 'bacteria Alcaligenes eutrophus Zl was studied. Two transitions on the catalytic activity of the enzyme vs redox potential profiles are observed: transitions with Em~—300 mV and Em~—400 mV control NAD(H)-dependent activities of enzyme and hydrogen uptake reaction with methyl viologen, respectively. These redox transitions may be accounted for by the model of the intramolecular electron transport chain of hydrogenase. A possible physiological role of the redox regulation of the hydrogenase catalytic activity is discussed. It is assumed that hydrogenase is regulated in vivo by the pool of nicotinamide adenine dinucleotides.