Selective labeling of beef heart cytochrome oxidase subunit III with eosin‐5‐maleimide

FEBS Letters

Azzi, Angelo¹  Müller, Michele¹ 

[1] Medizinisch-chemisches Institut der Universität Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland

关键词: Cytochrome oxidase;    Submit III;    Eosin-5-maleimide;    Selective labeling;    N;    N-Dicyclohexylcarbodiimide;    C12E10;    polyoxyethylene 10 laurylether;    DCCD;    dicyclohexylcarbodiimide;    EMA;    eosin-5-maleimide;   

DOI  :  10.1016/0014-5793(85)80664-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Cytochrome c oxidase has been isolated from beef heart mitochondria and labeled with the fluorochrome eosin-5-maleimide (EMA) after pretreatment with mersalyl. On SDS-polyacrylamide gels, EMA fluorescence and absorption occurred at a single band corresponding to subunit III. Since only Cys 115 of the two cysteinyl residues of subunit III had been shown to be reactive towards water-soluble SH-reagents, it was concluded that this residue was the one labeled by EMA. The EMA/enzyme ratio was about 1. Gel filtration experiments have shown that upon treatment with dicyclohexylcarbodiimide, subunit III was loosened from the complex; this result suggests that the inhibitory effect of dicyclohexylcarbodiimide on the H⁺-translocation activity may be related to such a phenomenon.

【 授权许可】

Unknown