Factors affecting the species-homologous and species-heterologous binding of mitochondrial ATPase inhibitor, IF1, to the mitochondrial ATPase of slow and fast heart-rate hearts
| Autor: | C.W. Broge, William Rouslin |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone
ATPase Submitochondrial Particles Biophysics Mitochondrion Biochemistry Mitochondria Heart Potassium Chloride Rats Sprague-Dawley Sonication Species Specificity Animals Submitochondrial particle Columbidae Molecular Biology chemistry.chemical_classification Membrane potential Adenosine Triphosphatases Lagomorpha biology ATPase complex Osmolar Concentration Proteins biology.organism_classification Rats Enzyme chemistry Enzyme inhibitor Nigericin biology.protein Cattle Rabbits |
| Zdroj: | Archives of biochemistry and biophysics. 303(2) |
| ISSN: | 0003-9861 |
| Popis: | We examined the effects of a variety of conditions upon the IF 1 -mediated inhibition of the ATPase in both intact and sonicated mitochondria and in IF 1 -depleted submitochondrial particles (SMP) in species-homologous and species-heterologous combinations of IF 1 and ATPase. IF 1 -mediated ATPase inhibition occurred in intact rabbit heart mitochondria at low matrix pH and low membrane potential, but not in intact pigeon and rat heart mitochondria under the same conditions. IF 1 -mediated ATPase inhibition was, however, demonstrable in both the rabbit and pigeon heart systems in sonicated mitochondria incubated at low ionic strength. The rat heart system failed to exhibit significant IF 1 -mediated ATPase inhibition in either intact or sonicated mitochondria due to the low amount of IF 1 present. When rabbit heart IF 1 -containing extracts were incubated with IF 1 -depleted rabbit heart SMP over a range of KCl concentrations, increasing the [KCl] to 100 mM had little effect on IF 1 -mediated ATPase inhibition. When pigeon heart IF 1 -containing extracts were incubated with IF 1 -depleted pigeon heart SMP under the same conditions, increasing [KCl] to 100 mM nearly completely blocked IF 1 -mediated ATPase inhibition. While the species-endogenous level of rat heart IF 1 (i.e., 1× IF 1 ) inhibited IF 1 -depleted rat heart SMP virtually not at all at any [KCl] examined, the 8× rat heart IF 1 was nearly as inhibitory as the 1× rabbit heart IF 1 at varying ionic strengths. When rabbit, pigeon, or rat heart IF 1 was bound to rabbit versus pigeon IF 1 -depleted SMP, the effect of varying ionic strength on IF 1 -mediated ATPase inhibition was related to the species source of the IF 1 , not to the species source of the enzyme; 1× bovine heart IF 1 purified to homogeneity behaved much like 1× crude rabbit heart IF 1 when binding to either the rabbit or the pigeon heart enzyme. This suggests that an IF 1 -ATPase complex stabilizing factor such as has been isolated from baker′s yeast cells is neither lacking in the pigeon heart system nor required for the more ionic-strength-resistant binding of IF 1 observed in slow heart-rate mammalian heart mitochondria. |
| Databáze: | OpenAIRE |
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