Purification and Properties of an Exo-α-l,3-glucanase fromTrichoderma viride

An α-l,3-glucanase was partially purified from Meicelase, a commercial cellulase preparation from T. viride, and its properties were studied. Cellulase in the crude enzyme was removed by adsorption on cellulose powder, and α-l,3-glucanase was purified through salting- out with ammonium sulfate, chromatographies on DEAE-Sephadex, hydroxylapatite and Sephadex G-100. The α-l,3-glucanase gave 2 peaks on DEAE-Sephadex chromatography, and the enzyme of the second peak was further purified to about 300-fold purification. The enzyme was most active at pH 4.5, and 55°C, stable at 4°C at pH between 3 and 7, and stable up to 50°C on heat treatment at pH 4.5 for 30 min. The Michaelis constant for α-l,3-glucan was 7.1 mM (as anhydroglucose units). The molecular weight of the enzyme determined by gel filtration on Sephadex G-100 was 47,000. Only glucose was formed as reducing sugar liberated from α-l,3-glucan, showing that the enzyme was an exo-α-l,3-glucanase (EC 3.2.1.84).