THE ACTIVITY OF LIPASE AT THE CUBIC LIQUID-CRYSTALLINE PHASE WATER INTERFACE

The activity of lipase from Humicola lanuginosa was investigated at th e cubic liquid-crystalline phase/water interface. For comparison, the activity of this lipase at an ordinary triglyceride/water interface wa s also determined. A cubic phase was formed by monoolein and water, an d triolein was used as reference. The sample were weighed into glass a mpoules, lipase solution was added, and lipolysis was followed by visu al observation and by photographing the sample at given time intervals (1 min, 30 min, 3 h, 9 h, and 24 h). Experiments were performed with lipase at a concentration of 0.2 mg/ml (6 muM) dissolved in distilled water and in buffers at pH 5, 7, and 10. At the end of the experiments , thin layer chromatography (TLC) was used to determine the compositio n of the samples. The results showed clear lipolysis in distilled wate r (pH 5 at the end of the experiments) and in buffers at pH 5 and 10. After approximately 30 h these samples were decomposed to oleic acid a rid glycerol. (C) 1994 Academic Press, Inc.