BETA-1,3-GLUCANASE AND DIMORPHISM IN PARACOCCIDIOIDES-BRASILIENSIS

Mycelial and yeast forms of P. brasiliensis were tested for several glucohydrolases. In addition to high levels of β-blucanases, low amounts of α-glucanase, chitinase and maltase were found. Tests for invertase, amylase and lactase were negative. The levels of β-1,3-glucanase were higher in the mycelial form. The shift to the mycelial phase correlated with an increase in the levels of β-1,3-glucanase. The enzyme was present in the cytoplasm, cell wall and culture medium. The extracellular enzyme was purified 42 fold by ammonium sulphate precipitation and gel filtration. Maximal activity was obtained at 60°C and pH of 5.0 acetate buffer or pH 6.0 (phosphate buffer). Its Km was 0.205 mg/ml. The cell wall-bound enzyme showed a higher temperature optimum. Optimum pH and Km were also slightly different. Following treatment of the cell walls with chitinase, β-1,3-glucanase was released into the medium. © 1979 H. Veenman & Zonen B.V.