POTENTIOMETRIC ANALYSIS OF THE PURIFIED CYTOCHROME-D TERMINAL OXIDASE COMPLEX FROM ESCHERICHIA-COLI
POTENTIOMETRIC ANALYSIS OF THE PURIFIED CYTOCHROME-D TERMINAL OXIDASE COMPLEX FROM ESCHERICHIA-COLI
复制标题
DOI：
10.1021/bi00301a003
复制
发表时间：
1984-01-01
期刊：
影响因子：
2.9
通讯作者：
GENNIS, RB
中科院分区：
文献类型：
--
作者：
KOLAND, JG;MILLER, MJ;GENNIS, RB
细胞色素d末端氧化酶复合体是大肠杆菌有氧呼吸链的主要组成部分。经十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析，该纯化配合物含有2个多肽，还原负氧化谱显示细胞色素b-558、a1和d均为该配合物的组分。分析了配合物在500 ~ 700 nm之间的吸收光谱随溶液电化学电位的变化规律。利用光谱分辨算法从络合物不同溶液电位下的光谱集中提取各电化学活性物质的还原-氧化谱。该过程产生了细胞色素b-558， a1和d的还原负氧化差谱，以及每个细胞色素的中点电位和能态n值。溶解配合物的中点电位（Em）和n值分别为：细胞色素b-558， Em = 61 mV, n = 0.8；细胞色素a1， Em = 113 mV, n = 1；细胞色素d， Em = 232 mV, n = 1。细胞色素b-558的光谱为典型的b型细胞色素，而细胞色素d的光谱以628 nm为中心的条带为主。细胞色素a1的差谱显示α。波段在594nm处，有很强的。560nm附近的波段和645nm附近的波谷。光谱与高自旋血红素a模型化合物的光谱相似。
The cytochrome d terminal oxidase complex is a principal component of the aerobic respiratory chain of E. coli. This purified complex contains 2 polypeptides as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the reduced minus oxidized spectrum indicates that cytochromes b-558, a1 and d are all components of the complex. Changes in the absorption spectrum of the complex between 500-700 nm were analyzed as a function of the solution electrochemical potential. A spectral resolution algorithm was used to extract the reduced minus oxidized spectrum of each electrochemically active species from the set of spectra of the complex at different solution potentials. The procedure yielded reduced minus oxidized difference spectra for cytochromes b-558, a1 and d, along with the midpoint potentials and Nernst n values for each cytochrome. The midpoint potentials (Em) and n values for the solubilized complex were as follows: cytochrome b-558, Em = 61 mV and n = 0.8; cytochrome a1, Em = 113 mV and n = 1; cytochrome d, Em = 232 mV and n = 1. The spectrum of cytochrome b-558 was typical of b-type cytochromes and that of cytochrome d was dominated by a band centered at 628 nm. The difference spectrum of cytochrome a1 indicated an .alpha. band at 594 nm, a strong .beta. band near 560 nm and a trough near 645 nm. The spectrum is similar to the spectra of high-spin heme a model compounds.