Inhibition by excess of free ATP, and free Mg2+ ions of the mitochondrial F1-ATPase moiety from Phycomyces blakesleeanus.
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.
de Vicente
J I
JI
Departamento de Bioquímica y Biología Molecular, Universidad León, Spain.
del Valle
P
P
Busto
F
F
de Arriaga
D
D
Soler
J
J
D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology*; D001665:Binding Sites; D006868:Hydrolysis; D008274:Magnesium / Q000494:pharmacology*; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology*; D009243:NAD / Q000378:metabolism; D010800:Phycomyces / Q000187:drug effects / Q000201:enzymology*; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors* / Q000378:metabolism
D009243:NAD; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases; D008274:Magnesium