Two modes of irreversible inactivation of the mitochondrial electron-transfer system by tetradecanoic acid.
Bovine heart submitochondrial particles were incubated for 2-6 h at 37 degrees C with various concentrations of tetradecanoic acid, and the effects on the activities, the total acid-labile sulphide content and EPR spectra of the electron transfer system were studied. Two distinct time-dependent processes of the slow irreversible inactivation of the electron-transfer system were found. They differ in the concentration of tetradecanoic acid required. The more specific effect, induced by 100-400 nmol tetradecanoic acid per mg protein, consists of a selective blockage of electron transfer between the Fe-S clusters of the NADH dehydrogenase and ubiquinone, without damage to any of the Fe-S clusters. Higher concentrations of tetradecanoic acid caused gradual destruction of all Fe-S clusters of NADH dehydrogenase and of the 3-Fe cluster of succinate dehydrogenase, leading to complete inactivation of both NADH and succinate oxidation.
Schewe
T
T
Albracht
S P
SP
Ludwig
P
P
Rapoport
S M
SM
D000818:Animals; D002417:Cattle; D004578:Electron Spin Resonance Spectroscopy; D004579:Electron Transport / Q000187:drug effects; D066298:In Vitro Techniques; D008929:Mitochondria, Heart / Q000187:drug effects* / Q000378:metabolism; D019814:Myristic Acid; D009227:Myristic Acids / Q000494:pharmacology*; D009245:NADH Dehydrogenase / Q000378:metabolism; D013367:Submitochondrial Particles / Q000378:metabolism; D013385:Succinate Dehydrogenase / Q000378:metabolism
D009227:Myristic Acids; D019814:Myristic Acid; D013385:Succinate Dehydrogenase; D009245:NADH Dehydrogenase