Purification and some properties of Candida albicans exo-1,3-beta-glucanase

An exo-1,3-beta-glucanase was purified from blastoconidia of Candida albicans 1001. The purified enzyme appeared as a single protein band by PAGE, and split into two subunits (Mr approximately 63,000 and 44,000) when analysed by SDS-PAGE. The pI of the enzyme was 4 and a Km of 1.7 mg ml-1 was estimated for laminarin as substrate. Despite its very reduced activity on the synthetic substrate p-nitrophenyl beta-D-glucoside, C. albicans exo-1,3-beta-glucanase hydrolysed 1,3-beta-glucan by an exo-splitting mechanism and was inhibited by glucono-delta-lactone and by Hg2+ and Ag+ cations. The active exo-glucanase was mainly located in the periplasm, but it was also present inside the cytoplasmic membrane in small amounts and was secreted into the culture medium. The electrophoretic mobility of the enzyme from all three locations was the same.