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ATPase activities in peroxisome-proliferating yeast.
1Department of Chemistry, University of Texas, Arlington 76019-0065.
Biochimica Et Biophysica Acta
|July 5, 1991
Summary
Yeast peroxisomal preparations contain ATPase activity. This study found most of this activity originates from mitochondria, not peroxisomes, based on biochemical and immunological evidence.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Biology
Background:
- Yeast peroxisomes were previously thought to possess a proton-pumping ATPase.
- Peroxisomal ATPase activity exhibited characteristics of both mitochondrial and plasma membrane ATPases.
Purpose of the Study:
- To investigate the origin of ATPase activity associated with yeast peroxisomes.
- To determine if peroxisomes contain a unique H(+)-ATPase distinct from other organelles.
Main Methods:
- Comparative biochemical analysis of ATPase activities in purified yeast mitochondria, plasma membranes, and peroxisomal preparations.
- Enzyme marker analysis using sucrose gradient fractionation.
- Immunological detection using Western blot analysis with antibodies against mitochondrial F1 subunit.
Main Results:
- ATPase activity in peroxisomal preparations strongly correlated with the mitochondrial marker cytochrome c oxidase.
- Peroxisomal and mitochondrial ATPase activities showed similar sensitivity to inhibitors like azide, DCCD, and venturicidin at pH 9.0.
- Immunological analysis confirmed the presence of mitochondrial F1 subunit in peroxisomal fractions, indicating mitochondrial contamination.
Conclusions:
- The majority of H(+)-ATPase activity found in yeast peroxisomal preparations is not intrinsic to peroxisomes.
- This activity is predominantly derived from contaminating mitochondria.
- Yeast peroxisomes likely do not possess a unique proton-pumping ATPase of their own.