A study on the mechanism of the vanadate-dependent NADH oxidation.
The mechanism of the vanadate (V(V]-dependent oxidation of NADH was different in phosphate buffers and in phosphate-free media. In phosphate-free media (aqueous medium or HEPES buffer) the vanadyl (V(IV] generated by the direct V(V)-dependent oxidation of NADH formed a complex with V(V). In phosphate buffers V(IV) autoxidized instead of forming a complex with V(V). The generated superoxide radical (O2-) initiated, in turn, a high-rate free radical chain oxidation of NADH. Phosphate did not stimulate the V(V)-dependent NADH oxidation catalyzed by O2--generating systems. Monovanadate proved to be a stronger catalyzer of NADH oxidation as compared to polyvanadate.
Liochev
S I
SI
Department of Bioenergetics, Bulgarian Academy of Sciences, Sofia.
Ivancheva
E A
EA
D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009243:NAD / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects*; D010710:Phosphates / Q000494:pharmacology; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet; D013482:Superoxide Dismutase / Q000378:metabolism; D014638:Vanadates / Q000494:pharmacology*
D010710:Phosphates; D009243:NAD; D014638:Vanadates; D013482:Superoxide Dismutase