Component of the alternative oxidase localized to the matrix surface of the inner membrane of plant mitochondria
- Molecular Cell Biology
In mitoplasts from Arum maculatum spadices, succinate dehydrogenase (EC 184.108.40.206) and the alternative, cyanide-resistant oxidase activity (measured as m-chlorobenzhydroxamic acid-sensitive duroquinol oxidation) was unaffected by treatment with trypsin. In contrast, when 85% inside-out submitochondrial particles were treated with trypsin the alternative oxidase activity was inhibited by about 50% and succinate dehydrogenase activity by about 40%. Thus, a trypsin-sensitive component of the alternative pathway is located on the inner surface of the inner mitochondrial membrane. After trypsin treatment of the inside-out submitochondrial particles the inhibited alternative oxidase activity was partly restored by including 0.7 M citrate in the assay medium. This indicates that trypsin does not destroy the active site but merely causes a conformational change in the enzyme, thereby lowering its activity.
- Biochemistry and Molecular Biology
- (Arum maculatum, Plant, Mitochondria)
- Alternative pathway
- Inside-out submitochondrial particle
- ISSN: 0014-5793