| Autor: |
Parenti-Castelli G, Sechi AM, Landi L, Cabrini L, Mascarello S, Lenaz G |
| Jazyk: |
angličtina |
| Zdroj: |
Biochimica et biophysica acta [Biochim Biophys Acta] 1979 Jul 10; Vol. 547 (1), pp. 161-9. |
| DOI: |
10.1016/0005-2728(79)90104-x |
| Abstrakt: |
We investigated the kinetics of mitochondrial ATPase in bovine heart mitochondria and submitochondrial particles upon treatment with phospholipase A2, or upon addition of n-butanol to perturb the lipid protein interactions. The changes observed are the following: (1) Lipid removal or perturbation with butanol is accompanied by loss of ATPase activity with decrease of both V and of the KM for ATP. (2) There are changes of activation energy of ATPase activity at temperatures above the discontinuity normally observed for membrane-bound enzymes in mitochondria. In particular, butanol abolishes the discontinuity, and induces a constant activation energy of about 32 kcal/mol in the range 8--37 degrees C. (3) Butanol modifies the pH dependence of ATPase shifting the pH optimum from around 10 to less alkaline values. The optimum for Mg2+ concentrations is increased by the solvent. (4) Treatment with phospholipase A2 results in a removal of oligomycin-sensitive ATPase, whereas butanol addition prevents oligomycin inhibition of ATPase. (5) In beef heart mitochondria, a spin-labelled analog of the inhibitor, dicyclohexyl carbodiimide, did not show any change in environment upon butanol addition, unlike that found in mitochondria from Saccharomyces cerevisiae. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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