gramicidin-a and dodecyl-sulfate

Lauryl sulfate inhibits the Deltamu;(H)(+)-dependent reverse electron transfer reactions catalyzed by NADH:ubiquinone oxidoreductase (Complex I) in coupled bovine heart submitochondrial particles and in vesicles derived from Paracoccus denitrificans. The inhibitor affects neither NADH oxidase (coupled or uncoupled) nor NADH:ferricyanide reductase and succinate oxidase activities at the concentrations that selectively prevent the succinate-supported, rotenone-sensitive NAD(+) or ferricyanide reduction. Possible uncoupling effects of the inhibitor are ruled out: in contrast to oligomycin and gramicidin, which increases and decreases the rate of the reverse electron transfer, respectively, in parallel with their coupling and uncoupling effects, lauryl sulfate does not affect the respiratory control ratio. A mechanistic model for the unidirectional effect of lauryl sulfate on the Complex I catalyzed oxidoreduction is proposed.

Topics: Animals; Bacterial Proteins; Cattle; Electron Transport; Electron Transport Complex I; Feedback, Physiological; Gramicidin; Kinetics; Mitochondrial Proteins; Models, Chemical; Myocardium; Oligomycins; Paracoccus denitrificans; Sodium Dodecyl Sulfate; Uncoupling Agents