title: Content and binding characteristics of the mitochondrial ATPase inhibitor, IF1, in the tissues of several slow and fast heart-rate homeothermic species and in two poikilotherms.
abstract: We determined the IF1 contents of pig, rabbit, rat, mouse, guinea pig, pigeon, turtle, and frog heart mitochondria and the effects of varying ionic strength upon the IF1-mediated inhibition of the ATPase activity of IF1-depleted rabbit heart mitochondrial particles (RHMP) by IF1-containing extracts from these same eight species. The IF1 binding experiments were run at both species-endogenous IF1 levels and at an IF1 level normalized to that present in rabbit heart mitochondria. When species-endogenous levels of rabbit heart IF1 or either species-endogenous or normalized levels of pig heart IF1 were incubated with RHMP over a range of KCl concentrations, increasing the [KCl] to 150 mM had relatively little effect on IF1-mediated ATPase inhibition. When either species-endogenous or normalized levels of guinea pig, pigeon, turtle, or frog heart IF1 were incubated with RHMP under the same conditions, increasing [KCl] to 150 mM nearly completely blocked IF1-mediated ATPase inhibition. While species-endogenous levels of rat and mouse heart IF1 inhibited the ATPase activity of RHMP virtually not at all at any [KCl] examined, normalized levels of rat and mouse IF1 inhibited the ATPase activity of RHMP to the same extents as species-endogenous levels of pig and rabbit heart IF1, respectively, in the presence of increasing [KCl]. These experiments suggest that, while pig and rabbit heart mitochondria contain a full complement of higher-affinity IF1, pigeon, guinea pig, turtle, and frog heart mitochondria cell contain essentially a full complement of a lower-affinity form of IF1.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Ohio 45267-0575, USA.
authors.forename: W
authors.initials: W
authors.lastname: Rouslin
authors.forename: G D
authors.initials: GD
authors.lastname: Frank
authors.forename: C W
authors.initials: CW
authors.lastname: Broge
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D010856:Columbidae; D006168:Guinea Pigs; D006339:Heart Rate; D008297:Male; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D008929:Mitochondria, Heart / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000378:metabolism; D008931:Mitochondria, Muscle / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors*; D011817:Rabbits; D011894:Rana pipiens; D051381:Rats; D017207:Rats, Sprague-Dawley; D013045:Species Specificity; D013367:Submitochondrial Particles / Q000378:metabolism; D013552:Swine; D014426:Turtles; D000097795:ATPase Inhibitory Protein
chemical_list: D011506:Proteins; D006180:Proton-Translocating ATPases; D000097795:ATPase Inhibitory Protein