한국 전통 메주로부터 분리 동정한 Bacillus subtilis PCA20-3이 생산하는 protease의 생산조건과 특성을 조사하였다. Protease의 생산 최적조건을 0.2% soytone, 2% starch, 0.1% $(NH_4)_2SO_4,;0.2%;CaCl_2,;0.01%;yeast;extract,;0.1%;K_2HPO_4,;0.1%;KH_2PO_4$, pH 7.0, 30에서 20시간이었다. 효소의 최적작용 pH와 온도는 6.0-11.0, $55^{circ}C$였고 pH $6.0{sim}11.0$의 범위와 $50^{circ}C$이하에서 안정하였다. 금속이온중 $Fe^{(2+)}$와 $Cu^{(2+)}$에 의해 효소활성이 저해되었다. 2mM의 phenymethanesulfonyl fluoride에 의해 89.2%의 활성이 저하되어, 활성 serine을 가진 serine protease임이 시사되었다. 조효소액의 Km값은 $5.0{ imes}10^{(-4)}M,;V_(max)$값은 $100;{mu}g/min$이었으며 bovine serum albumin, isolated soybean protein 보다 casein에 대해 초기 가수분해력이 높은 것으로 나타났다.
Protease production and its characteristics were investigated with Bacillus subtilis PCA20-3 which was isolated from Korean traditional meju. The optimum culture conditions of Bacillus subtilis PCA20-3 for the production of the protease were as follow: 0.2% soytone, 2% starch, 0.1% $(NH_4)_2SO_4,;0.2%;CaCl_2,;0.01%;yeast;extract,;0.1%; K_2HPO_4,;0.1%;KH_2PO_4,;pH;7.0,;30^{circ}C$ and 20 hrs. The optimum pH and temperature for enzyme activity of protease producing Bacillus subtilis PCA20-3 were pH 8.0-10.0 and $55^{circ}C$, respectively. The enzyme was relatively stable at pH $6.0{sim}11.0$ and at temperature below $50^{circ}C$. The activity of the enzyme was inhibited by $Fe^(2＋);and;Cu^(2＋)$. 2 mM phenymethanesulfonyl fluoride inhibited 89.2% of enzyme activity. This indicates that the enzyme is serine protease. The $K_m$ value was $5;{ imes};10^{-4};M,;V_{max};value;was;100;{mu}g/min$. This enzyme hydrolyzed casein more rapidly than bovine serum albumin.
