Kinetic and stability studies of penicillin acylase in reversed micelles

The main purpose of this work was to study the stability of a dimeric enzym e, penicillin acylase, in reversed micelles, Kinetic studies were carried o ut in order to understand the enzyme brhavlour in reversed micelles. The en zyme activity profile as a function of the water content of the system exhi bited three maxima at w(0) equal to 14, 20 and 23, which were assigned to t he light sub-unit, to the heavy sub-unit and to the enzyme itself. The effe ct of AOT concentration on the activity of penicillin acylase was also stud ied and an increase in the surfactant concentration, at a constant w(0) was shown to produce an increase in enzyme activity. The influence of the wate r content (w(0)). AOT and enzyme concentration on the enzyme stability in r eversed micelles was then investigated. Enzyme stabilisation by the addition of alcohols and sugars was examined an d the sugar alcohol mannitol shown to provide an increase of more than 300% in the retention of activity.