Amount and turnover rate of the F0F1-ATPase and the stoichiometry of its inhibition by oligomycin in Rhodospirillum rubrum chromatophores |
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Authors: | B Norling A Strid C Tourikas P Nyrén |
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Institution: | Department of Biochemistry, Arrhenius Laboratories for Natural Sciences, University of Stockholm, Sweden. |
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Abstract: | The amount of F1-ATPase in chromatophores from Rhodospirillum rubrum was determined by Western blotting using anti-RrF1 rabbit antibodies. 9.1 mmol F1 (mol bacteriochlorophyll)-1 was obtained or 14% of the total protein content of the chromatophores. The turnover rate of the F0F1-ATPase was 17 molecules ATP s-1 during synthesis, 2 molecules ATP s-1 during hydrolysis under coupled conditions with Mg2+ as the divalent cation, and 7 molecules ATP s-1 during hydrolysis in the presence of carbonyl cyanide p-trifluoromethoxyphenylhydrazone. Binding of 1 mol oligomycin/mol F0F1-ATPase was found to inhibit the activities of the enzyme completely. A single binding site was found with a Kd of approximately 2 microM. |
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