Search results for "Uncoupling Agents"
showing 4 items of 4 documents
DctA- and Dcu-independent transport of succinate in Escherichia coli : contribution of diffusion and of alternative carriers
2001
Quintuple mutants of Escherichia coli deficient in the C4-dicarboxylate carriers of aerobic and anaerobic metabolism (DctA, DcuA, DcuB, DcuC, and the DcuC homolog DcuD, or the citrate/succinate antiporter CitT) showed only poor growth on succinate (or other C4-dicarboxylates) under oxic conditions. At acidic pH (pH 6) the mutants regained aerobic growth on succinate, but not on fumarate. Succinate uptake by the mutants could not be saturated at physiological succinate concentrations (≤5 mM), in contrast to the wild-type, which had a K m for succinate of 50 µM and a V max of 35 U/g dry weight at pH 6. At high substrate concentrations, the mutants showed transport activities (32 U/g dry weigh…
Tigliane diterpenes from the latex of Euphorbia obtusifolia with inhibitory activity on the mammalian mitochondrial respiratory chain
2003
Abstract Six diterpenes isolated from the latex of Euphorbia obtusifolia Poir. (Euphorbiaceae) were evaluated for their inhibition of the NADH oxidase activity in submitochondrial particles from beef heart. 4,20-Dideoxyphorbol-12,13-bis(isobutyrate) was the most potent inhibitor and showed an inhibitory concentration with IC 50 value of 2.6±0.3 mM. In the present study, some structure–activity trends are suggested for the inhibitory activity of the mammalian mitochondrial respiratory chain of these natural product derivatives of 4-deoxyphorbol esters.
3-acetylaltholactone and related styryl-lactones, mitochondrial respiratory chain inhibitors.
2000
A novel furano-pyrone, 3-acetylaltholactone, and two other known styryl-lactones, altholactone and 5-acetoxyisogoniothalamin oxide, have been isolated from Goniothalamus arvensis (Annonaceae) stem bark. We report here the isolation and structural elucidation of these compounds with furane-pyrone and styryl-pyrone skeletons, postulating also for the first time their mechanism of cytotoxicity based on inhibition on mammalian mitochondrial respiratory chain.
Energy-Linked Reactions Catalyzed by the Purified ATPase Complex (F0F1) from Rhodospirillum rubrum Chromatophores
1980
1. The isolation of the F0F1-ATPase complex from Rhodospirillum rubrum chromatophores by the use of taurodeoxycholate is described. 2. The enzyme preparation contains about 12 polypeptides; five are subunits of the F1 moiety. 3. The ATPase activity of the purified enzyme is dependent on the addition of phospholipids. 4. Km-vales for Mg2+-ATP and Ca2+-ATP are similar to the values obtained for the membrane-bound enzyme. 5. The F0F1-ATPase complex is more than 70% inhibited by oligomycin and N,N′-dicyclohexyl-carbodiimide. 6. The F0F1-ATPase complex was integrated into liposomes. The reconstituted proteoliposomes catalyzed energy transduction as shown by ATP-dependent quenching of acridine dy…