Neutral Proteinases I and II of Aspergillus sojae

Abstract

Two neutral proteinases (I and II) of Aspergillus sojae were isolated from wheat bran culture by DEAE-cellulose chromatography. Neutral proteinase I was purified by sequential chromatography on columns of CM-cellulose, Sephadex G-100 and hydroxylapatite. Neutral proteinase II was purified by chromatographies on DEAE-Sephadex A-50, hydroxylapatite and Sephadex G-100. Crystalline preparation was obtained from neutral proteinase II, but not from neutral proteinase I. The purified preparation of each enzyme was found to be homogeneous on sedimentation analysis, disc electrophoresis and disc electrofocusing. A notable difference in specific activity was observed between the two neutral proteinases, i.e., 1,050 and 35 proteinase units per mg of enzyme protein for neutral proteinases I and II, respectively. Determination of the ultraviolet absorption spectra indicated that the at 280 mμ of neutral proteinases I and II were 16.7 and 9.0, respectively. The molecular weights of neutral proteinases I and II were est...