guanosine-diphosphate and 12-hydroxydodecanoic-acid

Fatty acid (FA) uniport via mitochondrial uncoupling protein (UcP) was detected fluorometrically with PBFI, potassium-binding benzofuran phthalate and SPQ, 6-methoxy-N-(3-sulfopropyl)-quinolinium, indicating K+ and H+, respectively. The FA structural patterns required for FA flip-flop, UcP-mediated FA uniport, activation of UcP-mediated H+ transport in proteoliposomes, and inhibition of UcP-mediated Cl- uniport by FA, were identical. Positive responses were found exclusively with FA which were able to flip-flop in a protonated form across the membrane and no responses were found with 'inactive' FA lacking the flip-flop ability. The findings support the existence of FA cycling mechanism.

Topics: Benzoates; Benzofurans; Biological Transport; Carrier Proteins; Chlorides; Ethers, Cyclic; Fatty Acids; Fluorescent Dyes; Fluorometry; Guanosine Diphosphate; Hydrogen-Ion Concentration; Ion Channels; Ionophores; Lauric Acids; Liposomes; Membrane Proteins; Mitochondrial Proteins; Potassium; Protein Binding; Protons; Quinolinium Compounds; Structure-Activity Relationship; Uncoupling Protein 1; Valinomycin