通过X射线吸收光谱法研究的细胞色素氧化酶的“过氧化物酶体”形式。
"Peroxidatic" form of cytochrome oxidase as studied by X-ray absorption spectroscopy.
作者信息
Chance B, Kumar C, Powers L, Ching Y C
出版信息
Biophys J. 1983 Dec;44(3):353-63. doi: 10.1016/S0006-3495(83)84309-4.
X-ray absorption spectroscopy shows pulsed oxidase to be similar to resting oxidase but to lack the sulfur bridge between iron and copper of active sites (Powers, L., Y. Ching, B. Chance, and B. Muhoberac, 1982, Biophys. J., 37[2, Pt. 2]: 403a. [Abstr.] ) The first shell ligands and bond lengths of the pulsed oxidase active site heme most clearly fit the ferric peroxidases from horseradish and yeast, and the pulsed oxidase cyanide compound resembles the low spin hemoprotein cyanide compounds. The structural results are consistent with an aquo or a peroxo form for pulsed oxidase as is also observed by optical studies. These structural and chemical data are consistent with a role for the pulsed forms in a cyclic peroxidatic side reaction in which the pulsed and pulsed peroxide compounds act as peroxide scavengers. The peroxidatic role of cytochrome oxidase in the nonsulfur bridged form suggests the renaming of the "oxygenated" or "pulsed" forms on a functional basis as "peroxidatic" forms of cytochrome oxidase.
X射线吸收光谱显示，脉冲氧化酶与静止氧化酶相似，但活性位点的铁和铜之间缺乏硫桥（Powers, L., Y. Ching, B. Chance, and B. Muhoberac, 1982, Biophys. J., 37[2, Pt. 2]: 403a. [摘要]）。脉冲氧化酶活性位点血红素的第一配位层配体和键长与辣根和酵母中的铁过氧化物酶最为吻合，且脉冲氧化酶氰化物化合物类似于低自旋血红素蛋白氰化物化合物。结构结果与光学研究中观察到的脉冲氧化酶的水合或过氧形式一致。这些结构和化学数据与脉冲形式在循环过氧化物酶副反应中的作用一致，在该反应中，脉冲和脉冲过氧化物化合物充当过氧化物清除剂。细胞色素氧化酶在非硫桥形式中的过氧化物酶作用表明，基于功能将“氧化”或“脉冲”形式重新命名为细胞色素氧化酶的“过氧化物酶”形式。
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