ATP synthesis in the disk membranes of rod outer segments of bovine retina.
ATP is synthesized on the disk membrane isolated from rod outer segments of the bovine retina. Together with a slow component which accounted for a constant rate of about 22 nmol ATP/min/mg of protein and which was due to the adenylate kinase activity, a fast component with a maximal activity of about 58 nmol ATP/min/mg of protein was measured at physiological calcium concentrations. This fast activity disappeared in the presence of the Ca(2+) ionophore A23187, was inhibited by vanadate or thapsigargin but not by oligomycin, suggesting that this ATP synthesis is due to the reversal functioning of the Ca(2+)-ATPase previously found on the disk membranes.
Pepe
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Istituto di Biofisica, Facoltá di Medicina, Universitá di Genova, Corso Europa, I-16132 Genoa, Italy. pepe@ibf.unige.it
Notari
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Cugnoli
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Panfoli
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Morelli
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D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000096:biosynthesis*; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002417:Cattle; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D012374:Rod Cell Outer Segment / Q000187:drug effects / Q000201:enzymology*; D019284:Thapsigargin / Q000494:pharmacology
D004791:Enzyme Inhibitors; D007476:Ionophores; D000001:Calcimycin; D000244:Adenosine Diphosphate; D019284:Thapsigargin; D000255:Adenosine Triphosphate; D000252:Calcium-Transporting ATPases; D002118:Calcium