Inhibition by excess of free ATP, and free Mg2+ ions of the mitochondrial F1-ATPase moiety from Phycomyces blakesleeanus
De Vicente, J.I.; del Valle, P.; Busto, F.; de Arriaga, D.; Soler, J.
Biochemistry International 24(2): 339-347
1991
ISSN/ISBN: 0158-5231 PMID: 1834062 Document Number: 386031
High concentrations of either Mg-ATP complex, free ATP, or free Mg2+ ions were inhibitors of the mitochondrial F1-ATPase moiety from Phycomyces blakesleeanus. Free Mg2+ acts as a linear competitive inhibitor with regard to Mg-ATP hydrolysis with a Ki value of 2.8 mM. The inhibition by free ATP was markedly biphasic and thus simple competitive inhibition alone is not sufficient to explain the inhibitory effect. From these results conclusions were drawn about the binding of the substrate, Mg-ATP complex, to the enzyme.