Ascorbate-mediated electron transfer in protein thiol oxidation in the endoplasmic reticulum.
Addition of, or gulonolactone oxidase-dependent in situ generation of, ascorbate provoked the oxidation of protein thiols, which was accompanied by ascorbate consumption in liver microsomal vesicles. The maximal rate of protein thiol oxidation was similar upon gulonolactone, ascorbate or dehydroascorbate addition. Cytochrome P450 inhibitors (econazole, proadifen, quercetin) decreased ascorbate consumption and the gulonolactone or ascorbate-stimulated thiol oxidation. The results demonstrate that the ascorbate/dehydroascorbate redox couple plays an important role in electron transfer from protein thiols to oxygen in the hepatic endoplasmic reticulum, even in gulonolactone oxidase deficient species.
Csala
M
M
Department of Medical Chemistry, Semmelweis University of Medicine, P.O. Box 260, H-1444, Budapest, Hungary.
Braun
L
L
Mile
V
V
Kardon
T
T
Szarka
A
A
Kupcsulik
P
P
Mandl
J
J
Bánhegyi
G
G
D000818:Animals; D001205:Ascorbic Acid / Q000037:antagonists & inhibitors / Q000502:physiology*; D065607:Cytochrome P-450 Enzyme Inhibitors; D004220:Disulfides / Q000378:metabolism; D004579:Electron Transport; D004721:Endoplasmic Reticulum / Q000201:enzymology / Q000378:metabolism* / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006168:Guinea Pigs; D006801:Humans; D050544:L-Gulonolactone Oxidase; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D010084:Oxidation-Reduction; D051381:Rats; D017208:Rats, Wistar; D013401:Sugar Alcohol Dehydrogenases / Q000037:antagonists & inhibitors / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013997:Time Factors
D065607:Cytochrome P-450 Enzyme Inhibitors; D004220:Disulfides; D004791:Enzyme Inhibitors; D013438:Sulfhydryl Compounds; D013401:Sugar Alcohol Dehydrogenases; D050544:L-Gulonolactone Oxidase; D001205:Ascorbic Acid