Males R G, Herring F G
Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada.
Biochim Biophys Acta. 1999 Jan 12;1416(1-2):333-8. doi: 10.1016/s0005-2736(98)00236-3.
The transmembrane permeability coefficient of the alpha-hydroxyacid, glycolic acid, has been measured for egg phosphatidylcholine large unilamellar vesicles. The determination of the vesicle concentration independent first-order rate constant for membrane transport and the permeability coefficient were made using an NMR technique employing shift agents. Both the temperature dependence and the dependence on cholesterol content were investigated. The activation energy and the Arrhenius pre-exponential factor were found to be dependent on the cholesterol content. A marked increase in both parameters was observed up to 20 mol% cholesterol, with a further, small increase up to 50%. The pH dependence of permeability was also investigated. An increase in permeability is observed with a decrease in pH, providing a possible explanation for the effectiveness of glycolic acid in skin treatment.
已测定了α-羟基酸乙醇酸对鸡蛋磷脂酰胆碱大单层囊泡的跨膜渗透系数。使用采用位移试剂的核磁共振技术测定了膜转运的囊泡浓度无关一级速率常数和渗透系数。研究了温度依赖性和对胆固醇含量的依赖性。发现活化能和阿仑尼乌斯指前因子取决于胆固醇含量。在胆固醇含量高达20摩尔%时，观察到这两个参数均显著增加，在高达50%时进一步小幅增加。还研究了渗透性的pH依赖性。随着pH值降低观察到渗透性增加，这为乙醇酸在皮肤治疗中的有效性提供了一种可能的解释。
