A contribution of the mitochondrial adenosinetriphosphatase inhibitor protein to the thermal stability of the F0F1-ATPase complex.
A complete inactivation is observed after a 3 min pre-incubation at 70 degrees C with mitochondrial F0F1-ATPase complex depleted of the ATPase natural inhibitor protein (ammonium-Sephadex submitochondrial particles) and activated MgATP-submitochondrial particles (particles that after a 4 h-pre-incubation at 42 degrees C released the endogenous inhibitor protein). However, latent MgATP-submitochondrial particles (particles containing the inhibitor protein) pre-incubated under the same conditions are totally inactivated only after 15 min of pre-incubation. When ammonium-Sephadex particles are reconstituted with 20 micrograms/ml of purified ATPase inhibitor protein there is an increase of 15-fold in the half-time for thermal inactivation (t0.5), showing that the inhibitor protein protects the mitochondrial F0F1-ATPase complex against thermal inactivation.
Saad-Nehme
J
J
Departamento de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Brazil.
Bezerra
A L
AL
Fornells
L A
LA
Silva
J L
JL
Meyer-Fernandes
J R
JR
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D004789:Enzyme Activation; D004795:Enzyme Stability; D006358:Hot Temperature; D007700:Kinetics; D008929:Mitochondria, Heart / Q000201:enzymology*; D011506:Proteins / Q000302:isolation & purification / Q000378:metabolism*; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D013367:Submitochondrial Particles / Q000201:enzymology*; D013816:Thermodynamics; D000097795:ATPase Inhibitory Protein
D000255:Adenosine Triphosphate; D011506:Proteins; D006180:Proton-Translocating ATPases; D000097795:ATPase Inhibitory Protein