Interaction of F1-ATPase and its inhibitor peptide. Effect of pH.
1. The inhibition of F1-ATPase by its natural peptide inhibitor is mixed non-competitive with two pH optimum values (5.5 and 8.2). 2. A two-step model for the interaction is suggested in which two enzyme conformations would exhibit different affinities for the peptide. 3. At low pH, interaction would be favoured. At high pH, a conformation (not susceptible to inhibition) changes into another (susceptible to inhibition) through the hydrolytic reaction stimulation, due to high pH.
de Miguel
C
C
Department of Biochemistry, University of Navarra, Pamplona, Spain.
Encío
I
I
López-Mortalla
N
N
Santiago
E
E
D000818:Animals; D002417:Cattle; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008930:Mitochondria, Liver / Q000201:enzymology; D011506:Proteins / Q000378:metabolism*; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D051381:Rats; D000097795:ATPase Inhibitory Protein
D011506:Proteins; D006180:Proton-Translocating ATPases; D000097795:ATPase Inhibitory Protein