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A study on the mechanism of the vanadate-dependent NADH oxidation

1988; Elsevier BV; Volume: 5; Issue: 5-6 Linguagem: Inglês

10.1016/0891-5849(88)90107-4

1873-4596

Stefan I. Liochev, E Ivancheva,

Polyoxometalates: Synthesis and Applications

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(v)) generated by the direct V(v)-dependent oxidation of NADH formed a complex with V(v). In phosphate buffers V(v) 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.