Studies on the Protease Constitution of Aspergillus oryzae

In order to elucidate the protease constitution of Aspergillus oryzae, systematic separation of proteases was elaborated by sequential chromatography on Amberlite CG–50, DEAE-Sephadex A–50 and CM-cellulose. As the results, three kinds of proteases, that is, acid-, neutral- and alkaline proteases were isolated and purified in crystalline form except neutral one. Purified neutral protease could not be crystallized, but was confirmed to be homogeneous by ultracentrifugal analysis. Besides these proteases, a new protease which was unknown up to the present in the constitution of Asp. oryzae proteases, was first isolated and designated as “semi-alkaline protease” according to its optimal pH.