Mechanism of action of bicarbonate on the mitochondrial ATPase: a new graphical analysis procedure based on a ligand substitution model.
A graphical method for analyzing the effects of modifiers on enzymes that do not yield linear Lineweaver-Burk double-reciprocal plots is proposed. To test the validity of the method it was applied to data published by Ebel and Lardy [(1975) (J. Biol. Chem. 250, 191-196) for the activation of the rat liver mitochondrial ATPase by bicarbonate and other anions. It was concluded that bicarbonate acts by displacing the ADP product but that it cannot effectively displace ATP. A new index to compare the different anions is suggested.
D000244:Adenosine Diphosphate / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology*; D001667:Binding, Competitive; D055598:Chemical Phenomena; D002621:Chemistry; D004789:Enzyme Activation / Q000187:drug effects; D007700:Kinetics; D008024:Ligands; D008433:Mathematics; D008930:Mitochondria, Liver / Q000201:enzymology*; D008956:Models, Chemical; D051381:Rats
D001639:Bicarbonates; D008024:Ligands; D000244:Adenosine Diphosphate; D000251:Adenosine Triphosphatases