Purification and properties of amylases extracellularly produced by an imperfect fungus, Fusidium sp. BX-1 in a glycerol medium

Amylases (I and II) extracellularly produced by an imperfect fungus, Fusidium sp. BX-1 in a medium containing glycerol as a carbon source, were purified as electrophoretically and isoelectrophoretically homogeneous proteins. The electrophoretical mobilities of amylase I and II on native and SDS-polyacrylamide gels exactly coincided with each other. Their molecular weights were estimated to be about 52,000. The sugar contents of amylase I and II were 3.4 and 4.7%, and the pIs were 8.70 and 8.55, respectively. The K m s of the enzymes for soluble starch were 0.053 and 0.044%. The actions of the enzymes on soluble starch, short chain amyloses, and maltose were examined. Amylase I and II are identified as being to an α-amylase and a glucoamylase, respectively.