Component of the alternative oxidase localized to the matrix surface of the inner membrane of plant mitochondria

• In mitoplasts from Arum maculatum spadices, succinate dehydrogenase (EC 1.3.99.1) 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.

Ämnesord

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

Nyckelord

(Arum maculatum, Plant, Mitochondria)

Alternative pathway

Inside-out submitochondrial particle

Mitoplast

Trypsin

Publikations- och innehållstyp

art (ämneskategori)

ref (ämneskategori)