title: Uptake of basic amino acids and peptides into liposomes in response to transmembrane pH gradients.
abstract: The uptake of derivatives of lysine and a pentapeptide (ala-met-leu-trp-ala) into large unilamellar vesicle (LUV) systems in response to transmembrane pH gradients has been examined. In these derivatives, the C-terminal carboxyl functions have been converted to methyl esters or amides. It is shown that the presence of a pH gradient (interior acidic) results in the rapid and efficient accumulation of these weak base amino acid and peptide derivatives into LUVs in a manner consistent with permeation of the neutral (deprotonated) form. It is suggested that this property may have general implications for mechanisms of transbilayer translocation of peptides, such as signal sequences, which exhibit weak base characteristics.
authors.affiliation: Department of Biochemistry, University of British Columbia, Vancouver, Canada.
authors.forename: A C
authors.initials: AC
authors.lastname: Chakrabarti
authors.forename: I
authors.initials: I
authors.lastname: Clark-Lewis
authors.forename: P R
authors.initials: PR
authors.lastname: Harrigan
authors.forename: P R
authors.initials: PR
authors.lastname: Cullis
mesh_terms: D000595:Amino Acid Sequence; D000599:Amino Acids, Diamino / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008081:Liposomes; D008239:Lysine; D008433:Mathematics; D008564:Membrane Potentials; D008744:Methylamines; D008954:Models, Biological; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry*; D009861:Onium Compounds; D009943:Organophosphorus Compounds; D010713:Phosphatidylcholines
chemical_list: D000599:Amino Acids, Diamino; D008081:Liposomes; D008744:Methylamines; D009842:Oligopeptides; D009861:Onium Compounds; D009943:Organophosphorus Compounds; D010713:Phosphatidylcholines; C027451:methylamine; D008239:Lysine; C013289:tetraphenylphosphonium