Phase Transition in a Phosphatidylcholine Membrane Induced by Halogenated Alcohol

Abstract

The effects of halogenated alcohol on the phase transitions of dipalmitoylphosphatidylcholine (DPPC) were investigated. Differential scanning calorimetry (DSC) was used to study the gel-to-liquid-crystalline phase transitions. A biphasic behavior takes place in DPPC with halogenated alcohol. The transition temperature from the gel to a liquid-crystalline phase (T_m) decreases with increasing concentration of halogenated alcohol in aqueous solution. Above the threshold concentration, T_m increases with increasing the concentration in the solution. Except for bromopropanol, the transition temperature decreases again at a much higher concentration and a third-phase region is formed. The biphasic or triphasic behavior of DPPC with halogenated alcohol is as follows: bromoalcohol gives rise to a larger shift of T_m at the threshold concentration than chloroalcohol. The curvature of T_m at the threshold concentration was larger in the case of longer-chain halogenated alcohol.