Vygodina T V, Berka V, Ruuge E K, Konstantinov A A
A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, USSR.
FEBS Lett. 1992 Feb 3;297(1-2):63-6. doi: 10.1016/0014-5793(92)80328-e.
Superoxide dismutase is shown to affect spectral changes observed upon cytochrome c oxidase reaction with H2O2, which indicates a possibility of O2- radicals being formed in the reaction. Using DMPO as a spin trap, generation of superoxide radicals from H2O2 in the presence of cytochrome oxidase is directly demonstrated. The process is inhibited by cyanide and is not observed with a heat-denatured enzyme pointing to a specific reaction in the oxygen-reducing centre of cytochrome c oxidase. The data support a hypothesis on a catalase cycle catalyzed by cytochrome c oxidase in the presence of excess H2O2 (Vygodina and Konstantinov (1988) Ann. NY Acad. Sci., 550, 124-138): (formula: see text)
超氧化物歧化酶被证明会影响细胞色素c氧化酶与H2O2反应时观察到的光谱变化，这表明反应中可能形成了O2-自由基。使用DMPO作为自旋捕捉剂，直接证明了在细胞色素氧化酶存在下H2O2产生超氧自由基的过程。该过程受到氰化物的抑制，而热变性酶则未观察到这种现象，这表明细胞色素c氧化酶的氧还原中心存在特定反应。这些数据支持了一个关于在过量H2O2存在下由细胞色素c氧化酶催化的过氧化氢酶循环的假说（维戈迪娜和康斯坦丁诺夫（1988年）《纽约科学院学报》，550，124 - 138）：（公式：见原文）
