Parameters characterizing acid-base equilibria between cell membrane and solution and their application to monitoring the effect of various factors on the membrane

The cell membrane is an extremely complicated object. It participates in a large number of equilibria. For this reason, it is impossible to determine the parameters of all of them. It is the purpose of this work to define a limited number of averaged parameters in order to describe the equilibria between cell membrane components and environmental components. These parameters are the total acidic functional group concentration as well as the basic group concentration and their association constants with hydrogen or hydroxyl ions. The parameters were determined using the pH dependence of the electric surface charge density. The usefulness of these parameters was checked by studying the effect of green tea on liver cells in ethanol poisoning. Ethanol provokes an increase in concentration of functional groups, positively and negatively charged, as well as an increase in the basic groups association constant and a decrease in acidic groups association constant. Administering green tea partly compensates the changes provoked by ethanol poisoning. The parameters proposed in this work, C-TA, C-TB, K-AH and K-BOH, are suited for monitoring the changes caused by various factors. (c) 2006 Elsevier B.V All rights reserved.