Purification and some properties of a beta-glucanase from a strain, Trichoderma reesei GXC

摘要

beta-glucanase was purified from a solid-state culture of Trichoderma reesei on wheat bran in three steps which comprised ammonium sulfate precipitation, Sephadex G-100 chromatography, and DEAE-Sephadex A-50 chromatography. The molecular mass was determined to be 35.21 kilodaltons by sodium dodecyl sulfate-12.5 percent polyacrylamide gel electrophoresis. The beta-glucanase at low pHs was more stable than that at high pHs, and optimum pH was 5.0. The optimum temperature was 60 deg C, and beta-glucanase was relatively stable at below 40 deg C for 60 min. The K_m of the enzyme on beta-glucan was 10.86 mg/ml, and the V_(max) on beta-glucan was 14286 mu mol of glucose equivalents per mg of the pure enzyme per min. The beta-glucanase activity was significantly inhibited by Fe~(3+) ions, and was reduced in the presence of Cu~(2+) ions, Mn~(2+) ions and Mg~(2+) ions at 5 mmol/L and 10 mmol/L, respectively. The beta-glucanase activity was stimulated by Co~(2+) ions, Ca~(2+) ions, Zn~(2+) ions, and Fe~(2+) ions at 1 mmol/L and 5 mmol/L, respectively.