A clarification of the effects of DCCD on the electron transfer and antimycin binding of the mitochondrialbc 1 complex |
| |
Authors: | Mauro Degli Esposti Giorgio Lenaz |
| |
Affiliation: | (1) Institute of Botany, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy |
| |
Abstract: | We have studied in detail the effects of dicyclohexylcarbodiimide (DCCD) on the redox activity of the mitochondrialbc1 complex, and on the binding of its most specific inhibitor antimycin. An inhibitory action of the reagent has been found only at high concentration of the diimide and/or at prolonged times of incubation. Under these conditions, DCCD also displaced antimycin from its specific binding site in thebc1 complex, but did not apparently change the antimycin sensitivity of the ubiquinol-cytochromec reductase activity. On the other hand, using lower DCCD concentrations and/or short times of incubation, i.e., conditions which usually lead to the specific inhibition of the proton-translocating activity of thebc1 complex, no inhibitory effect of DCCD could be detected in the ubiquinol-cytochromec reductase activity. However, a clear stimulation of the rate of cytochromeb reduction in parallel to an inhibition of cytochromeb oxidation has been found under these conditions. On the basis of the present work and of previous reports in the literature about the effects of DCCD on thebc1 complex, we propose a clarification of the various effects of the reagent depending on the experimental conditions employed. |
| |
Keywords: | bc1 complex DCCD ubiquinol-cytochromec reductase antimycin pre-steady-state kinetics cytochromeb beef heart mitochondria |
本文献已被 SpringerLink 等数据库收录! |
|