title: Inactive fatty acids are unable to flip-flop across the lipid bilayer.
abstract: Free fatty acids (FA) were found which did not acidify liposome interior. This is interpreted as their inability to rapidly flip-flop across the lipid bilayer. However, they were able to partition in lipids as detected directly using HPLC or from the shift of their equilibrium binding to acrylodated intestinal binding protein (ADIFAB) in the presence of vesicles. Various bipolar FA, such as 12-hydroxylauric acid, dicarboxylic acids, or FA with benzene ring at the tail were found to be inactive in this way. A phenomenon of shielding, where an additional alkyl chain or non-polar group can restore the flip-flop activity, is described.
authors.affiliation: Institute of Physiology, Department of Membrane Transport Biophysics, Academy of Sciences of the Czech Republic, Prague. jezek@sun1.biomed.cas.cz
authors.forename: P
authors.initials: P
authors.lastname: Jezek
authors.forename: M
authors.initials: M
authors.lastname: Modrianský
authors.forename: K D
authors.initials: KD
authors.lastname: Garlid
mesh_terms: D002352:Carrier Proteins / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D005456:Fluorescent Dyes; D006863:Hydrogen-Ion Concentration; D007476:Ionophores / Q000494:pharmacology; D007700:Kinetics; D008051:Lipid Bilayers / Q000378:metabolism*; D008081:Liposomes / Q000378:metabolism; D011485:Protein Binding; D011522:Protons; D011806:Quinolinium Compounds; D011994:Recombinant Proteins; D014634:Valinomycin / Q000494:pharmacology
chemical_list: D002352:Carrier Proteins; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D005456:Fluorescent Dyes; D007476:Ionophores; D008051:Lipid Bilayers; D008081:Liposomes; D011522:Protons; D011806:Quinolinium Compounds; D011994:Recombinant Proteins; C079339:acrylodated intestinal fatty acid binding protein, recombinant; D014634:Valinomycin; C052335:6-methoxy-N-(3-sulfopropyl)quinolinium