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Effects of bc 1 ‐site electron transfer inhibitors on the absorption spectra of mitochondrial cytochromes b
Author(s) -
Kamensky Yuriy,
Konstantinov Alexander A.,
Kunz Wolfram S.,
Surkov Sergey
Publication year - 1985
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(85)81120-0
Subject(s) - antimycin a , chemistry , absorption (acoustics) , electron transfer , binding site , mitochondrion , coenzyme q – cytochrome c reductase , stereochemistry , biophysics , biochemistry , photochemistry , biology , cytochrome c , physics , acoustics
Changes are described that are brought about by antimycin, NoHOQnO, funiculosin, myxothiazol and mucidin in the α‐, β‐ and γ‐absorption bands of reduced and oxidized cytochromes b in the isolated complex bc 1 , form beef heart mitochondria. The inhibitors can be divided into 2 groups. Antimycin, funiculosin and NoHOQnO are likely to shift the spectrum of b ‐562 and compete for specific binding with complex bc 1 with each other but not with myxothiazol and mucidin. The spectral effects of the latter two inhibitors are more difficult to interpret and may involve contributions not only from b ‐562 but from b ‐566 as well. The existence of 2 independent inhibitor binding‐sites in the complex bc 1 corroborates the Q‐cycle hypothesis.