Villalba J M, Canalejo A, Burón M I, Córdoba F, Navas P
Departamento de Biología Celular, Universidad de Córdoba, Spain.
Biochem Biophys Res Commun. 1993 Apr 30;192(2):707-13. doi: 10.1006/bbrc.1993.1472.
Plasma membranes purified by two-phase partition from rat liver showed an NADH-ascorbate free radical reductase activity of about 14 nmoles NADH oxidized/min/mg protein. This activity was inhibited by N-ethyl maleimide, iodoacetate and iodoacetamide, reagents that covalently block thiol groups. NADH-ascorbate free radical reductase was also inhibited by reduced glutathione and the inhibitions observed with blocking reagents and reduced compounds were additive. These results support the involvement of sulphydryl groups in NADH-AFR reductase and point out the idea that a balance between reduced sulfhydryls and oxidized disulfides is required for the optimal function of this activity, considered as part of the transplasma membrane electron transport system.
通过两相分配法从大鼠肝脏中纯化得到的质膜显示出约14纳摩尔NADH氧化/分钟/毫克蛋白质的NADH-抗坏血酸自由基还原酶活性。这种活性受到N-乙基马来酰亚胺、碘乙酸盐和碘乙酰胺的抑制，这些试剂可共价阻断巯基。NADH-抗坏血酸自由基还原酶也受到还原型谷胱甘肽的抑制，并且观察到的阻断试剂和还原型化合物的抑制作用是相加的。这些结果支持了巯基参与NADH-AFR还原酶的观点，并指出这样一种观点，即这种被视为跨质膜电子传递系统一部分的活性的最佳功能需要还原型巯基和氧化型二硫键之间的平衡。
