β-1, 3-Glucanase from trichoderma viride. Purification and characterization

The extracellular complex of β-glucanases produced by the mould Trichoderma viride hydrolyzes β-1,3-; β-1,4- and β-1, 6-bonds of β-glucans, as well as mixed β-1,3- and β-1,4-glycosidic linkages. This complex contains also xylanase. The enzymes were isolated from liquid culture medium by centrifuge techniques, concentration and precipitation with acetone. Isolation and purification of β-1,3-glucanase was carried out according to a procedure involving filtration on Bio-Gel P-100, DEAE-Sephadex A 50 and CM-cellulose C-11 chromatography, ultrafiltration and selective adsorption on xylan. The homogeneity of the enzyme was determined by polyacrylamidegel electrophoresis. The purified homogeneous preparation of the isolated β-1,3-glucanase from Tr. riride was subjected to detailed characterization. Amino acid composition, molecular weight and optimum conditions for the enzymatic activity of the protein were determined. The isolated enzyme was shown to be highly specific to substrates with β-1,3-glycosidic linkages; the rate of degradation was found to be proportional to the degree of polymerization of the substrate.