Oxygenated complex of cytochrome bd from Escherichia coli:: Stability and photolability
Oxygenated complex of cytochrome bd from Escherichia coli:: Stability and photolability
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DOI：
10.1016/j.febslet.2005.07.011
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发表时间：
2005-08-29
期刊：
影响因子：
3.5
通讯作者：
Verkhovsky, MI
中科院分区：
文献类型：
--
作者：
Belevich, I;Borisov, VB;Verkhovsky, MI
细胞色素bd是大肠杆菌呼吸链中两个末端泛醇氧化酶之一，催化o2还原为H2O。酶在低氧张力下表达；由于对O-2的高亲和力，它主要作为稳定的含氧配合物被分离出来。直接测量O-2在单电子还原分离酶中与血红素d结合的K-d（O2）近似为280 nM。在微氧条件下，通过酶的光照几分钟，可以光解血红素d氧络合物；光诱导差异吸收光谱实际上与02与血红素结合的倒置光谱相同。(c) 2005年欧洲生化学会联合会。Elsevier B.V.版权所有。
Cytochrome bd is one of the two terminal ubiquinol oxidases in the respiratory chain of Escherichia coli catalyzing reduction of O-2 to H2O. The enzyme is expressed under low oxygen tension; due to high affinity for O-2 it is isolated mainly as a stable oxygenated complex. Direct measurement of O-2 binding to heme d in the one-electron reduced isolated enzyme gives K-d(O2) of similar to 280 nM. It is possible to photolyse the heme d oxy-complex by illumination of the enzyme for several minutes under microaerobic conditions; the light-induced difference absorption spectrum is virtually identical to the inverted spectrum Of 02 binding to heme d. (c) 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.