PURIFICATION AND CHARACTERIZATION OF AN ENDO-BETA-1,3-GLUCANASE FROM TRICHODERMA-HARZIANUM

beta-1,3-Glucanases are produced by Trichoderma harzianum when it is g rown in the presence of chitin or isolated cell wall from fungi. An en do-beta-1,3-glucanase from the culture filtrate of T. harzianum was pu rified by gel filtration on Sephacryl S-200, followed by hydrophobic i nteraction chromatography on phenyl-Sepharose. A typical procedure pro vided 134-fold purification with a 3.6% yield. The molecular mass of t he purified endo-beta-1,3-glucanase was found to be approximately 36 k Da, as estimated by sodium dodecyl sulfate - polyacrylamide gel electr ophoresis on a 10% w/v slab gel. The enzyme was active toward glucans containing beta-1,3-linkages and hydrolysed laminarin to form oligosac charides. The K-m and V-max values for beta-1,3-glucanases, using lami narin as substrate, was 1.18 mg . mL(-1) and 1.26 U . mL(-1), respecti vely. The pH optimum for the enzyme was pH 4.4 and maximum activity wa s obtained at 45 - 50 degrees C. Enzyme activity was strongly inhibite d in the presence of HgCl2 and stimulated by cations such as Zn2+ and Ca2+.