SOLUBILIZATION AND IDENTIFICATION OF ESSENTIAL FUNCTIONAL-GROUPS OF CANDIDA-ALBICANS OXIDOSQUALENE CYCLASE

The enzyme properties and location of essential functional groups of s olubilized oxidosqualene cyclase of Candida albicans have been studied . We show that the C. albicans enzyme is much more heat-labile compare d with Saccharomyces cerevisiae and rat liver cyclases, requires a his tidyl residue for enzyme activity, contains an essential thiol residue either close to or in the active site and exhibits a carbocationic me chanism for catalysis, as the enzyme-bound substrate protects the enzy me from inactivation by a site-directed inactivator.