Tissue-specific regulation of bovine heart cytochrome-c oxidase activity by ADP via interaction with subunit VIa.
The activity of reconstituted cytochrome-c oxidase (EC 1.9.3.1) from bovine heart is stimulated by intraliposomal ADP but not by NaCl of the same ionic strength. A monoclonal antibody which reacts with subunits VIa-H (heart-type) and VIc, due to the evolutionary relationship between these subunits, also stimulates the activity of the enzyme from bovine heart but not from bovine liver. The antibody induces a conformational change in the heart enzyme but not in the liver enzyme, as shown by the visible difference spectrum. Preincubation of heart cytochrome-c oxidase with the antibody prevents stimulation of activity by intraliposomal ADP after reconstitution in liposomes. Reconstituted liver cytochrome c oxidase is not stimulated by intraliposomal ADP. The data suggest tissue-specific regulation of the activity of cytochrome-c oxidase by ADP via interaction with the matrix domain of subunit VIa-H.
Fachbereich Chemie (Biochemie), Philipps-Universität, Marburg, Federal Republic of Germany.
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Anthony
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Reimann
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Kadenbach
D000244:Adenosine Diphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D002417:Cattle; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D008929:Mitochondria, Heart / Q000201:enzymology; D008930:Mitochondria, Liver / Q000201:enzymology; D008969:Molecular Sequence Data; D009206:Myocardium / Q000201:enzymology*; D016415:Sequence Alignment
D000911:Antibodies, Monoclonal; D046911:Macromolecular Substances; D008565:Membrane Proteins; D000244:Adenosine Diphosphate; D003576:Electron Transport Complex IV