Effect of fatty acids on H+ transport activity of the reconstituted uncoupling protein.

摘要: A detailed study on the activation of H+ transport by reconstituted uncoupling proteins from brown adipose tissue is given, including influence chain lengths and other structural modifications, concentration dependence, nucleotides. Uncoupling protein was with phosphatidylcholine in such a way as to keep endogenous fatty acids at minimum. Using excess polystyrene beads reconstitution avoided complications arising use albumin. Both delta psi-driven uptake efflux systems are used changing polarity. Fatty stimulate up 6-fold more than 10-fold. There no competition between inhibition nucleotides (GTP) acids. Also, binding GTP ATP not affected. Only starting C8 activate, reaching maximum C14. However, unsaturated homologous C18 (oleic, linoleic, etc.) fully active. Hydrophilic substitutions hydroxyl, CO2H, bromo, doxyl groups also permit good activation, probably due improved into lipid phase. The hydrophobic moiety exhibits low specificity. Blockage carboxyl esterification abolishes activation. Maximum requires high total concentrations 200-300 microM. distribution proteoliposomes solution determined. mode discussed either regulatory activators or cofactors translocation involving their groups. Two alternatives considered, namely that group center channel facilitating transfer constituent H(+)-translocating