In:
FEBS Letters, Wiley, Vol. 462, No. 1-2 ( 1999-11-26), p. 192-198
Abstract:
Low (C 1/2 =1.5×10 −7 M) concentrations of horse cytochrome c strongly inhibit H 2 O 2 production by rat heart mitochondria under conditions of reverse electron transfer from succinate to NAD + . The effect is abolished by binding of cytochrome c with liposomes and is not prevented by SOD. Yeast cytochrome c is much less effective than the horse protein whereas acetylated horse cytochrome c is without effect. H 2 O 2 formation stimulated by antimycin A is resistant to added cytochrome c . In inside‐out submitochondrial vesicles, H 2 O 2 production is suppressed by all three cytochrome c samples tested, but at higher concentrations (C 1/2 is about 5×10 −7 M). In vesicles, SOD abolishes the cytochrome c inhibition. We conclude that extramitochondrial cytochrome c is competent in down‐regulation of the Complex I H 2 O 2 production linked to the reverse electron transfer. Such an effect is absent in the inside‐out submitochondrial vesicles where another antioxidant cytochrome c function can be observed, i.e. the oxidation of O 2 − to O 2 . A possible role of cytochrome c in the antioxidant defence is discussed.
Type of Medium:
Online Resource
ISSN:
0014-5793
,
1873-3468
DOI:
10.1016/S0014-5793(99)01525-2
Language:
English
Publisher:
Wiley
Publication Date:
1999
detail.hit.zdb_id:
1460391-3
SSG:
12
