Purification and properties of a glucoamylase fraction from the culture filtrate of Rhizopus nodosus.

A glucoamylase was isolated from the culture filtrate of Rhizopus nodosus and was separated from the acid lipase by DEAE-cellulose chromatography at pH 8.0 It was purified by Concanavalin A Sepharose 4B affinity chromatography followed by CM-Sephadex chromatography 387 fold with 30.7% yield. The homogeneity of the enzyme were confirmed by polyacrylamide gel electrophoresis and immunological studies. The different physico-chemical properties of the enzyme were studied. The molecular weight of the enzyme was found to be 71,000. Ethylenediaminetetraacetic acid had no effect on the enzyme whereas Hg2+ partially inhibited the enzyme activity. Tryptophan residues were found to be essential for the enzyme activity.