Aerobic, inactive forms of Azotobacter vinelandii hydrogenase: activation kinetics and insensitivity to C2H2 inhibition.
Azotobacter vinelandii hydrogenase (EC class 1.12), either purified or membrane-associated, was obtained aerobically in an inactive state. The kinetics of activation by treatment with a reductant (H2 or dithionite) were determined. Three distinct phases of the activation were observed. Aerobically prepared, inactive hydrogenase was insensitive to acetylene inhibition, but could be rendered acetylene-sensitive by reduction with dithionite. These findings indicate that acetylene inhibition of hydrogenase requires catalytically active enzyme.
D000114:Acetylene / Q000494:pharmacology*; D000332:Aerobiosis; D001395:Azotobacter / Q000201:enzymology*; D002462:Cell Membrane / Q000201:enzymology; D004789:Enzyme Activation; D006859:Hydrogen; D006864:Hydrogenase / Q000037:antagonists & inhibitors*; D007700:Kinetics; D010084:Oxidation-Reduction
D006859:Hydrogen; D006864:Hydrogenase; D000114:Acetylene