Purification and Properties of Neutral Proteinase II from Aspergillus oryzae

Abstract

Neutral proteinase II (the second peak in DEAE-cellulose chromatography) in the culture fluid of Aspergillus oryzae was purified the Amberlite IRC-50 adsorbed fraction by DEAE-cellulose chromatography and two steps of gel filtration through Sephadex G-100. The purified enzyme showed neither aminopeptidase nor carboxypeptidase activity. The molecular weight of the enzyme was estimated to be about 19, 300 by gel filtration method. The enzyme has an optimum pH of 5.5 to 6.0 in acetate and phosphate buffers. More than 70% of the activity was remained after heating at 90°C for 10min. About 70% of original activity was reduced in the presence of 10-2M EDTA (pH 6.0) and the activity with 18% NaCI was almost 50% of the activity without NaCl.