电子传递链的四种复合物 a、NADH脱氢酶复合物:含42个蛋白亚基,至少6个Fe-S中心, 1个黄素蛋白 作用:催化NADH氧化,从中获得2高能电子→辅酶Q;泵出4 H b、琥珀酸脱氢酶复合物:含FAD辅基,2Fe-S中心, 作用:催化2高能电子→FAD→Fe-S→辅酶Q(无H泵出) c、细胞色素bc复合物:包括 Icytc、 Icyt b、IFe-S蛋白 作用:催化电子从UQH2→cytc;泵出4H d、细胞色素C氧化酶:二聚体,每一单体含13个亚基,三维构 象,cyta,cyta3,Cu,Fe 作用:催化电子从cytc→分子O2形成水
电子传递链的四种复合物 a、NADH脱氢酶复合物：含42个蛋白亚基，至少6个Fe-S中心， 1个黄素蛋白。 作用：催化NADH氧化，从中获得 2高能电子➔辅酶Q；泵出4 H+ b、琥珀酸脱氢酶复合物：含FAD辅基，2Fe-S中心， 作用：催化2高能电子➔FAD➔Fe-S➔辅酶Q(无H+泵出) c、细胞色素bc1复合物：包括1cyt c1、1cyt b、1Fe-S蛋白 作用：催化电子从UQH2➔cyt c；泵出4 H+ d、细胞色素C氧化酶：二聚体，每一单体含13个亚基，三维构 象， cyt a, cyt a3 ,Cu, Fe 作用：催化电子从cyt c➔分子O2 形成水
Cytochrom NADH-CoC Intermembrane Cyt c, CooH Inner FMN membrane Fe. Cytb CoOH Matrix 4H NAD' CoQH2-cyt c 2H NADH reductase complex V207+2H H2o Succinate-Coo reductase complex 2H Fe-S Coos-CoaH Fes Fes 少 Con merate CoQHr-cyt c Succinate FIGURE 16-19: The pathway of electron transport(blue arrows) and proton transport (red arrows)in the inner mitochondrial membrane Bound to each of the electron transport complexes are several prosthetic groups, which carry electrons through the complex ( Top) A pair of electrons from one NADH first move through the NADH-CoQ reductase complex to one coenzyme Q( CoQ) molecule, which binds reversibly to the com- plex. The reduced CoHz diffuses in the membrane and donates electrons to the CoQHz-Cyt c reductase complex. The peripheral protein cyto- chrome c diffuses in the intermembrane space, transporting electrons (one at a time)from the CoQH2-Cyt c reductase complex to the cyto- chrome c oxidase complex and ultimately to O2 Protons are pumped from the matrix into the intermembrane space at the indicated sites. The protons released into the matrix space by the oxidation of NAdh are consumed in the formation of water from oz, resulting in no net proton translocation from these reactions. Thus a total of 10 protons are translocated per pair of electrons moved from NADH to O2 (Bottom)The succinate-coQ reductase complex oxidizes succinate to fumarate, reducing one CoQ to CoQH No protons are translocated by the succinate- CoQ reductase complex. The remainder of electron transport from succinate proceeds by the same path as in the top diagram. Thus for every pair of electrons transported from succinate to O, six protons are translocated from the matrix into the intermembrane space