Phospholipid release from sonicated vesicles induced by a "critical" fatty acid concentration

Dipalmitoyl phosphatidylcholine vesicles incubated in the presence of increasing amounts of myristic acid showed a progressive translocation of phospholipid molecules across a dialysis membrane. The rate of phospholipid translocation increased abruptly at a 'critical' value of myristic acid concentrations. The translocation rate of mixed dipalmitoyl phosphatidylcholine/myristic acid vesicles obtained by cosonicating the two components was also dependent on a 'critical' fatty acid concentration. A marked release of K+ and different responses of fluorescent probes to the fatty acid addition were observed at this concentration.