Electron transfer between cytochrome c and the binuclear center of cytochrome oxidase

JOURNAL OF THEORETICAL BIOLOGY

卷:460

Article

Rocha, Mariana¹  Springett, Roger¹ 

[1] Kings Coll London, British Heart Fdn, Ctr Excellence, Cardiovasc Div, London, England

关键词: Cytochrome oxidase;    Enzyme kinetics;    Enzyme modeling;    Midpoint potential;    Redox anti-cooperativity and proton pumping;   

DOI  :  10.1016/j.jtbi.2018.10.022

来源: Elsevier

【 摘 要 】

The Minnaert model, which can account for the reaction kinetics between cytochrome oxidase and cytochrome c (Cytc), has been used to justify equal binding rate constants for reduced and oxidized Cytc. Here we extend the model beyond reversible binding of Cytc and its irreversible oxidation to include Cu-A, heme a and the oxidation cycle of the binuclear center. The model reproduces the experimental reduction of Cu-A and heme a during turnover and the low population of the ferryl and ferrous heme a(3). It predicts that the off rate constants for reduced and oxidized Cytc can be unequal and that the non Nernst response of Cu-A and heme a is due to disequilibrium between free Cytc and Cu-A rather than redox anticooperativity. (C) 2018 Elsevier Ltd. All rights reserved.

【 授权许可】

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