Steady‐state kinetics of F1‐ATPase

Abstract
The kinetic behaviour of the ATPase activity of beef heart F1 depends largely on the exposure of the enzyme to some anionic ligands such as sulphate and/or EDTA. F1 prepared in the presence of such anions exhibited a triphasic kinetic pattern whereas F1 from which those anions were removed by dialysis exhibited only two K m values for ATP. Conversely to what has been previously reported, bicarbonate did not linearize F2‐ATPase kinetics. Moreover, anion activation cannot be simply explained by promotion of ADP release but mainly by an increase in affinity of the third catalytic site for ATP.