Second harmonic studies of ions crossing liposome membranes in real time.
The transport kinetics of the positively charged triphenylmethane dye, malachite green (MG(+)), across liposome bilayers effects the transport of monovalent inorganic cations when ionophores are present in the membrane. Three different types of ionophores characterized by different transport mechanisms have been studied. The ionophores are gramicidin A (gA) (a channel former), valinomycin (VAL) (a lipophilic cyclopeptide that encloses an alkali ion), and carbonyl cyanide-m-chlorophenylhydrazone (CCCP) (a weak acid that functions as a protonophore). The effects of these ionophores on the kinetics and extent of MG(+) crossing into the liposome, investigated using the interface selective second harmonic generation method, were found to be markedly different.
Liu
Jian
J
Department of Chemistry, Columbia University, New York, New York 10027, USA.
Subir
Mahamud
M
Nguyen
Kim
K
Eisenthal
Kenneth B
KB
D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000737:chemistry; D006096:Gramicidin / Q000737:chemistry; D007477:Ions; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D008274:Magnesium / Q000737:chemistry; D008567:Membranes, Artificial; D010539:Permeability; D014634:Valinomycin / Q000737:chemistry
D007477:Ions; D008051:Lipid Bilayers; D008081:Liposomes; D008567:Membranes, Artificial; D006096:Gramicidin; D014634:Valinomycin; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D008274:Magnesium