钒酸盐依赖的NADH氧化机制的研究

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

作者信息

Liochev S I, Ivancheva E A

机构信息

Department of Bioenergetics, Bulgarian Academy of Sciences, Sofia.

出版信息

Free Radic Biol Med. 1988;5(5-6):349-54. doi: 10.1016/0891-5849(88)90107-4.

DOI:10.1016/0891-5849(88)90107-4

PMID:3256532

Abstract

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.

摘要

钒酸盐（V(V)）依赖的NADH氧化机制在磷酸盐缓冲液和无磷酸盐介质中有所不同。在无磷酸盐介质（水性介质或HEPES缓冲液）中，由V(V)直接依赖氧化NADH产生的氧钒（V(IV)）与V(V)形成复合物。在磷酸盐缓冲液中，V(IV)发生自氧化而非与V(V)形成复合物。生成的超氧自由基（O2-）继而引发NADH的高速自由基链氧化。磷酸盐不会刺激由O2-生成系统催化的V(V)依赖的NADH氧化。与多钒酸盐相比，单钒酸盐被证明是更强的NADH氧化催化剂。