Diphosphatidylglycerol reactivation of lipid-depleted beef heart cytochrome c oxidase: effect of subunit III removal.
Beef heart cytochrome c oxidase can be fully delipidated by Triton X-100 using an alkaline pH, high ionic strength incubation followed by glycerol gradient centrifugation at pH 8 in 1% Triton X-100. Unfortunately, this procedure removes not only the 2-3 diphosphatidylglycerol (DPG) molecules that are tightly bound to each heme aa3 complex, but also removes subunit III. A one-to-one correlation exists between the percent of subunit III removed and the percent of tightly bound DPG extracted, suggesting a possible tight binding of these two molecules. However, based upon regeneration of most of the electron transport activity of the subunit III deficient complex by exogenous DPG, it appears that the functional DPG binding site must be located on a subunit other than subunit III.
Robinson
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Wiginton
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D000818:Animals; D002308:Cardiolipins / Q000494:pharmacology*; D002417:Cattle; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects*; D004793:Enzyme Reactivators; D046911:Macromolecular Substances; D008563:Membrane Lipids / Q000502:physiology*; D009206:Myocardium / Q000201:enzymology; D017830:Octoxynol; D011092:Polyethylene Glycols / Q000494:pharmacology
D002308:Cardiolipins; D004793:Enzyme Reactivators; D046911:Macromolecular Substances; D008563:Membrane Lipids; D011092:Polyethylene Glycols; D017830:Octoxynol; D003576:Electron Transport Complex IV