Cénas N K, Bironaité D A, Kulys J J, Sikhova N M
Institute of Biochemistry, Lithuanian Academy of Sciences, Vilnius, U.S.S.R.
Biochim Biophys Acta. 1991 Jan 23;1073(1):195-9. doi: 10.1016/0304-4165(91)90201-q.
Nitrofurans inhibit the oxidation of NADPH by glutathione, catalyzed by yeast glutathione reductase (EC 1.6.4.2). acting as uncompetitive incomplete inhibitors for NADPH and glutathione. The quinoline-substituted nitrofurans were the most effective inhibitors. These compounds increased the turnover numbers of enzyme at fixed concentrations of reduced glutathione, in the reverse reaction of glutathione reductase, but in most cases diminished the affinity of the enzyme for NAD+. Nitrofurans are weak one-electron oxidants of glutathione reductase. Their reactivity is close to that of p-quinones possessing the analoguous one-electron reduction potential (Cénas, N.K., Rakauskiené, G.A. and Kulys, J.J. (1989) Biochim. Biophys. Acta 973, 399-404), and reaction is stimulated by NADP+. It is assumed, that nitrofurans bind to the 'regulative' site of glutathione reductase (Karplus, P.A., Pai, E.F. and Schulz, G.E. (1989) Eur. J. Biochem. 178, 693-703).
硝基呋喃可抑制酵母谷胱甘肽还原酶（EC 1.6.4.2）催化的谷胱甘肽对NADPH的氧化反应，作为NADPH和谷胱甘肽的非竞争性不完全抑制剂。喹啉取代的硝基呋喃是最有效的抑制剂。在谷胱甘肽还原酶的逆反应中，这些化合物在固定浓度的还原型谷胱甘肽下增加了酶的周转数，但在大多数情况下降低了酶对NAD+的亲和力。硝基呋喃是谷胱甘肽还原酶的弱单电子氧化剂。它们的反应活性与具有类似单电子还原电位的对醌接近（Cénas, N.K., Rakauskiené, G.A. 和 Kulys, J.J. (1989) Biochim. Biophys. Acta 973, 399 - 404），并且反应受NADP+刺激。据推测，硝基呋喃与谷胱甘肽还原酶的“调节”位点结合（Karplus, P.A., Pai, E.F. 和 Schulz, G.E. (1989) Eur. J. Biochem. 178, 693 - 703）。
