Katsuobushi에서 분리한 Aspergillus niger 균주에서 생산한 조효소로부터 정제한 protease의 최적 pH와 온도는 pH 7.2와 $45^{circ}C$였으며, $pH;5{sim}6$ 범위내에서 $40^{circ}C$ 이하에서 안정하였으며, 금속이온의 영향은 $K^{-}$와 $Fe^{2+}$는 효소활성을 증진시켰고 $Zn^{2},;Mn^{2}$ 및 $Cd^{3}$등은 효소활성을 저해하였으며, 구성아미노산은 산성아미노산이 22.6%, 염기성아미노산이 13.57%. 중성아미노산이 63.8%였으며, 비극성아미노산, 극성아미노산 및 함황아미노산의 구성비는 각각 39.72%, 23.03% 및 9.35%이었다. 분자량은 42000, 등전점은 pH 5.6이었다.
Protease was purified from Aspergillus niger propagated on katsuobushi. The optimal pH and temperature of the enzyme were 7.2 and $45^{circ}C$, respectively. The enzyme was stable at $pH;5{sim}8$ and at below $40^{circ}C$. Enzyme activity was promoted by $K^{-};and;Fe^{2+}$, whereas it was inhibited by $Hg^{2},;Zn^{2},;Mn^{2};and;Cd^{2}$. The acidic, basic and neutral amino acid compositions were found to be 22.63, 13.57 and 63.80%, respectively. The content of nonpolar, poler and sulfur-containing amino acids were 39.72, 20.03 and 9.53% respectively, and aspartic and glutamic acids were abundant. The molecular weight was 42,000 and isoelectric point was estimated pH 5.6.
