Abstract
N,N''-Dicyclohexylcarbodiimide [DCCD] at low concentrations decreases the H+/2e ratio for rat liver mitochondria over the span succinate to oxygen from 5.9 .+-. 0.3 (mean .+-. SEM [standard error of the mean]) to 4.0 .+-. 0.1 and for the cytochrome b-c1 complex from 3.8 .+-. 0.2 to 1.9 .+-. 0.1, but has little effect on the H+/2e ratio of cytochrome oxidase. The decrease in stoichiometry is due, not to uncoupling or inhibition of electron transport, but to inhibition of proton translocation. DCCD thus decouples proton translocation in the cytochrome b-c1 complex.