Reduction of Acetylene and Hydrazine with (ATP requirement/nitrogenase comparison)

Crystalline preparations of a molyb- denum-glutathione complex catalyze the reduction of acetylene to ethylene in the presence of borohydride. The reaction proceeds at rates up to 6 mol of C2H2 produced per min per mol of bound Mo, which is 4% of the activity of a quantity of nitrogenase with an equivalent amount of Mo. The activity of the complex is enhanced 100-fold by ATP, but the addition of ADP has no effect. Stimulation in activity by GTP is about the same as that by ATP, and the effects of CTP or UTP are considerably less. Inhibition of acetylene-reduction activity by the addition of 32 mM orthophosphate was 14%, by 32 mM pyrophosphate 62%, by 0.2 atm of 02 65%, and by 0.5 atm of CO 12%; 0.5 atm of H112 had no effect. The molybdenum-glutathione complex also catalyzes the reduction of hydrazine to ammonia in a reaction that is dependent upon borohydride. The reaction is enhanced about 7-fold by ATP and proceeds at a rate of 2 mol of NH3 produced per min per mol of bound Mo.