The effect of n-alcohols on vesicular permeability induced at the lipid phase transition temperature: a 1H-NMR study.
The effect of a series of n-alcohols on the permeability of small, unilamellar dipalmitoyl phosphatidylcholine (DPPC), dimyristoyl phosphatidylcholine (DMPC) and distearoyl phosphatidylcholine (DSPC) vesicles at the gel-to-liquid crystal phase transition temperature was investigated. It was found that the permeability took the form of the transient lysis of a fraction of the population of vesicles. The effect on this lysis of the n-alcohols was seen to be very chain-length dependent, with a minimum at n = 8 (octan-1-ol) for DPPC vesicles. A similar minimum was observed in the presence of 0.1 mM Triton X-100, but the detergent could then interact with certain of the alcohols to produce permanent channels. The results are discussed in terms of the semi-empirical model of Brasseur et al. (1985) Biochim. Biophys. Acta 814, 227-236, for the interaction of the n-alcohols with a DPPC membrane. The effect of various n-alcohols on the outer and inner monolayers of DPPC vesicles was also studied and the results related to their fluidising effect, allowing channels to open at the phase transition temperature.
Department of Science, Polytechnic of Wales, Pontypridd, Mid Glamorgan, U.K.
G R
GR
Hunt
M
M
Kaszuba
D000438:Alcohols; D005782:Gels; D006859:Hydrogen; D008051:Lipid Bilayers; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008962:Models, Theoretical; D008968:Molecular Conformation; D010539:Permeability; D010713:Phosphatidylcholines; D013816:Thermodynamics
D000438:Alcohols; D005782:Gels; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D006859:Hydrogen