Proton translocation by cytochrome oxidase in (antimycin + myxothiazol)-treated rat liver mitochondria using ferrocyanide or hexammineruthenium as electron donor.
Proton translocation by cytochrome oxidase in (antimycin + myxothiazol)-treated rat liver mitochondria using ferrocyanide or hexammineruthenium as electron donor.
复制标题
使用亚铁氰化物或六氨钌作为电子供体，在（抗霉素粘噻唑）处理的大鼠肝线粒体中通过细胞色素氧化酶进行质子易位。
作者：
I. West;R. Mitchell;A. Moody;P. Mitchell
当将 O2 注射到用鱼藤酮、抗霉素和 myxothiazol 抑制的缬氨霉素处理的大鼠肝线粒体的厌氧悬浮液中时，少量 O2（0.23-0.33 纳克原子 O/mg 蛋白质）极快地减少（在氧电极的 2 s 时间分辨率内）。随后电子流向氧气的稳态速率非常低[小于 3 nequiv。 X s-1 X（线粒体蛋白克数）-1]。在缬氨霉素存在的情况下，质子快速喷射，与 O2 消耗的快速阶段同步，对应于 0.38-0.61 nequiv。 H+ X（线粒体蛋白毫克）-1。当用羰基氰化物对三氟甲氧基苯腙（FCCP）代替缬氨霉素时，介质迅速碱化，相当于0.20-0.42当量。 H+ X（线粒体蛋白毫克）-1。当 2 mM-Fe(CN)6(4-) 存在以重新减少内源细胞色素 c 时，O2 消耗仍然是双相的，但 O2 消耗的第二阶段要快得多 [600 nequiv。 X s-1 X（蛋白质克）-1]，并导致脉冲中的 O2 在 4 秒内几乎完全消耗。使用 60 microM-Ru(NH3)6(2+) 作为还原剂，O2 消耗甚至更快 [1200 nequiv。 X s-1 X (g 蛋白质)-1]。在含有 150 mM 氯化胆碱并以 Ru(NH3)6(2+) 作为还原剂的培养基中，每还原当量化学计量的质子 (δ H+O/e-) 在缬氨霉素存在下为 +0.95，在 FCCP 存在下为 -0.94。在含有Ru(NH3)6(2+)和缬氨霉素的氯化胆碱培养基中，K+离子的吸收相当于1.86K+/e-。结论是，每注入该介质中的氧化当量，就有近 1 个质子通过细胞色素氧化酶向外移位。在低离子强度蔗糖培养基中，以 Ru(NH3)6(2+) 作为还原剂，在缬氨霉素存在下，δ H+O/e- 为 1.05，在 FCCP 存在下，δ H+O/e- 为 -0.71。结论是质子的易位伴随着该介质中的净酸产生。
When O2 was injected into an anaerobic suspension of valinomycin-treated rat liver mitochondria inhibited with rotenone, antimycin, and myxothiazol, a small amount of O2 (0.23-0.33 ng-atom of O/mg of protein) was reduced extremely rapidly (within the 2 s time-resolution of the oxygen electrode). The subsequent steady-state rate of flow of electrons to oxygen was very low [less than 3 nequiv. X s-1 X (g of mitochondrial protein)-1]. In the presence of valinomycin there was a rapid ejection of protons synchronous with the rapid phase of O2 consumption corresponding to 0.38-0.61 nequiv. of H+ X (mg of mitochondrial protein)-1. When valinomycin was replaced by carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) there was a rapid alkalification of the medium corresponding to 0.20-0.42 nequiv. of H+ X (mg of mitochondrial protein)-1. When 2 mM-Fe(CN)6(4-) was present to re-reduce endogenous cytochrome c, O2 consumption was still biphasic but the second phase of O2 consumption was very much more rapid [600 nequiv. X s-1 X (g of protein)-1], and resulted in the virtually complete consumption of the O2 in the pulse within 4 s. With 60 microM-Ru(NH3)6(2+) as reductant, O2 consumption was even faster [1200 nequiv. X s-1 X (g of protein)-1]. In a medium containing 150 mM-choline chloride with Ru(NH3)6(2+) as reductant, the proton per reducing equivalent stoichiometry (delta H+O/e-) was +0.95 in the presence of valinomycin and -0.94 in the presence of FCCP. In choline chloride medium containing Ru(NH3)6(2+) and valinomycin, there was an uptake of K+ ions corresponding to 1.86 K+/e-. It is concluded that nearly 1 proton is translocated outwards through cytochrome oxidase per oxidizing equivalent injected in this medium. In low ionic strength sucrose-based medium, with Ru(NH3)6(2+) as reductant, delta H+O/e- was 1.05 in the presence of valinomycin, and -0.71 in the presence of FCCP. It is concluded that the translocation of protons is accompanied by net acid production in this medium.