Purification and Properties of Extracellular Acid Phosphatase from Zizania latifolia-parasite, Ustilago esculenta

Abstract

An extracellular acid phosphatase from Ustilago esculenta was purified to homogeneity on the basis of polyacrylamide gel electrophoresis. It was a glycoprotein with an isoelectric point of 4.7. The molecular weight of the enzyme was estimated to be about 343, 000 by gel filtration on Sephadex G-200, whereas on SDS-polyacrylamide gel electrophoresis, the enzyme gave a single protein band with a molecular weight of 116, 000. This result suggests that the enzyme consists of three identical subunits. The enzyme showed an optimum activity at pH 4.5, retained 90% of its activity for 10 min at 55°C and had a Km value of 0.25 mM for p-nitrophenylphosphate. No definite substrate specificity of the enzyme was observed.