Brittain T, Little R H, Greenwood C, Watmough N J
Centre for Metalloprotein Spectroscopy and Biology, School of Biological Sciences, University of East Anglia, Norwich, UK.
FEBS Lett. 1996 Dec 9;399(1-2):21-5. doi: 10.1016/s0014-5793(96)01253-7.
We have re-examined the reaction of fast oxidised cytochrome bo with H202 in a stopped-flow spectrophotometer. Monitoring the reaction at 582 nm allows us to observe the formation and decay of a spectroscopically distinct intermediate which accumulates transiently prior to the formation of an oxyferryl species previously characterised in this laboratory (Watmough, N.J., Cheesman, M.R., Greenwood, C. and Thomson, A.J. (1994) Biochem. J. 300, 469-475 [1]). The reaction shows three distinct phases of which the fast and intermediate phases are bimolecular and show a marked pH dependence. Initially these results appeared incompatible with the report that only one equivalent of H202 is required to generate the oxyferryl species (Moody, A.J. and Rich, P.R. (1994) Eur. J. Biochem. 226, 731-737 [21]. However, these data can be reconciled by a branched reaction mechanism whose contributions differ according to the peroxide concentration used.
我们在停流分光光度计中重新研究了快速氧化的细胞色素 bo 与 H₂O₂ 的反应。在 582 nm 处监测该反应，使我们能够观察到一种光谱上不同的中间体的形成和衰减，该中间体在先前本实验室表征的氧铁物种形成之前短暂积累（瓦特莫，N.J.，奇兹曼，M.R.，格林伍德，C. 和汤姆森，A.J.（1994 年）《生物化学杂志》300 卷，469 - 475 页 [1]）。该反应呈现出三个不同阶段，其中快速和中间阶段是双分子的，并且表现出明显的 pH 依赖性。最初，这些结果似乎与仅需一当量 H₂O₂ 就能生成氧铁物种的报道不一致（穆迪，A.J. 和里奇，P.R.（1994 年）《欧洲生物化学杂志》226 卷，731 - 737 页 [21]）。然而，这些数据可以通过一种分支反应机制来协调，其贡献根据所使用的过氧化物浓度而有所不同。
