Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Benzoates / metabolism
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Benzofurans / metabolism
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Biological Transport
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Carrier Proteins / metabolism*
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Chlorides / metabolism
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Ethers, Cyclic / metabolism
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Fatty Acids / chemistry
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Fatty Acids / metabolism*
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Fluorescent Dyes / metabolism
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Fluorometry
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Guanosine Diphosphate / pharmacology
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Hydrogen-Ion Concentration
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Ion Channels
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Ionophores / pharmacology
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Lauric Acids / metabolism
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Liposomes / metabolism
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Membrane Proteins / metabolism*
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Mitochondrial Proteins
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Potassium / metabolism
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Protein Binding
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Protons
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Quinolinium Compounds / metabolism
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Structure-Activity Relationship
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Uncoupling Protein 1
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Valinomycin / pharmacology
Substances
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Benzoates
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Benzofurans
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Carrier Proteins
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Chlorides
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Ethers, Cyclic
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Fatty Acids
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Fluorescent Dyes
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Ion Channels
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Ionophores
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Lauric Acids
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Liposomes
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Membrane Proteins
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Mitochondrial Proteins
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Protons
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Quinolinium Compounds
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Uncoupling Protein 1
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potassium-binding benzofuran isophthalate
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Guanosine Diphosphate
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Valinomycin
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12-hydroxydodecanoic acid
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6-methoxy-N-(3-sulfopropyl)quinolinium
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Potassium