Kinetics of CO binding to H+‐motive oxidases of the caa 3‐type from Bacillus FTU and of the o‐type from Escherichia coli

[摘要]

The kinetics of CO rebinding with isolated Bacillus FTU caa ₃-type oxidase and with solubilized Escherichia coli membranes (GO103 strain) containing the o-type oxidase as the main O₂reducing enzyme were studied under reducing conditions by laser flash photolysis of the CO-oxidase complexes. The spectra of the optical absorbance changes upon photolysis were characteristic of CO-caa ₃ and CO-o-oxidase complexes in Bac. FTU and E.Coli, respectively. Small quantities of d-type oxidase in E.Coli GO103 membranes were detected. The kinetics of CO reassociation with reduced caa ₃ and o-type oxidases were monophasic with τ 25–30 ms in both cases.

[学科分类] 生物化学/生物物理

[关键词] Flash photolysis;caa 3Type oxidase;o-Type oxidase;Bacillus FTU;Escherichia coli;TMPD;N;N;N'N'-tetramethyl-p-phenylendiamine;PAG;polyacrylamide gel;Δ̃smH +;the proton electrochemical gradient