Kinetic Properties of Hxdrogenase Isolated from Desulfovibrio vulgaris (Hildenborough)

Publisher Website
Google Scholar
Abstract
Hydrogenase of D. vulgaris shows nonlinear kinetics in H2 production with the natural electron carrier, cytochrome c3, and the artificial donor, methyl viologen semiquinone. Increasing concentrations of salt progressively inhibit the H2 production, as do increasing amounts of dimethylsulfoxide (Me2SO). H2 consumption activity does not change up to 30% (vol/vol) of Me2SO. Preincubation in Me2SO up to 55% (vol/vol) does not affect the H2 uptake or production. The production activity of the enzyme shows an optimum around pH 6. When plotted as a function of redox potential the activity can be fitted to a Nernst equation with n = 1. Midpoint potentials calculated at various values follow approximately the H electrode to pH 6; thereafter, there is a shift of about 40 mV to higher redox potentials.