Tert-butyl hydroperoxide selectively inhibits mitochondrial respiratory-chain enzymes in isolated rat hepatocytes.
Sensitivity of various mitochondrial enzymes to oxidative damage was tested on isolated rat liver hepatocytes permeabilized by digitonin. In permeabilized hepatocytes normal respiratory control values were obtained and mitochondrial membranes remained intact. Respiratory rates of NADH-dependent (glutamate + malate, palmitylcarnitine + malate) and flavoprotein-dependent (succinate) substrates were determined in hepatocytes exposed for 5 min to 0.5-3 mM tert-butyl hydroperoxide before addition of digitonin. Our data showed that oxidation of NADH-dependent substrates is much more sensitive to oxidative stress than oxidation of flavoprotein-dependent ones, evidently due to the modification of iron-sulfur clusters or SH groups in the NADH dehydrogenase enzyme complex (Complex I).
Drahota
Z
Z
Institute of Physiology and Center for Integrated Genomics, Academy of Sciences of the Czech Republic, 14220 Prague 4, Vídenská 1083, Czech Republic. drahota@biomed.cas.cz
Kriváková
P
P
Cervinková
Z
Z
Kmonícková
E
E
Lotková
H
H
Kucera
O
O
Houstek
J
J
D000818:Animals; D004072:Digitonin; D004579:Electron Transport / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism*; D066298:In Vitro Techniques; D007202:Indicators and Reagents; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects / Q000201:enzymology*; D009243:NAD / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013379:Substrate Specificity; D020122:tert-Butylhydroperoxide / Q000494:pharmacology*
D007202:Indicators and Reagents; D009243:NAD; D020122:tert-Butylhydroperoxide; D004072:Digitonin