Abstract
The major amylolytic enzyme present in Meicelase, a commercial crude cellulase preparation from Trichoderma viride, was purified by consecutive column chromatography, and characterized as a glucoamylase [EC 3.2. 1.3] . The specific activity was brought to 18.3 units of soluble starch-saccharifying activity/mg of enzyme protein, and the enzyme showed a single band on polyacrylamide gel disc electrophoresis . Some properties of the purified glucoamylase were investigated . The optimum pH and the optimum temperature for the activity of the enzyme were pH 5 .0-5.5 and 60°C, respectively. The enzyme was stable over the range pH 5.0-7.0 at 4°C and was completely inactivated by heating at 90°C for 10 min. Hg2+ completely inhibited the enzyme, but other metalions tested had little effect on the activity at the concentration of ions used (1 mM) . The action of the enzyme on amylopectin, glycogen, soluble starch, short chain amylose (DP=17.3), maltose, isomaltose and panose was studied. Glucose was the sole hydrolysis product found in digests of these substrates. At the same substrate concentration (0.075%, w/v) and enzyme concentration, the initial rates of glucose production from amylopectin, soluble starch, short chain amylose and maltose were in the proportions 8 : 8 : 8 : 1.
