Purification and properties of extracellular carboxyl proteinase secreted by Candida pulcherrima.

An extracellular proteinase secreted by Candida pulcherrima KSY 188-5 was purified about 60-fold to electrophoretical homogeneity from its culture supernatant, by ammonium sulfate fractionation, anion-exchange chromatography, and gel filtration. The proteinase had a molecular weight of approximately 36,500 and an isoelectric point of pH 4.7. The enzyme had an optimum pH of around 2.5-3.5 for activity and 3.0-5.0 for stability. The optimum temperature was around 45 degrees C at pH 3.0. The enzyme showed a broad substrate specificity for a variety of proteins to hydrolyze casein, BSA, hemoglobin keratin, and collagen. Among several proteinase inhibitors, pepstatin A completely abolished the enzyme activity; indicating that the extracellular proteinase from C. pulcherrima KSY 188-5 was classified in the group of carboxyl proteinases.