Abstract
These experiments were conducted to investigate the enzymatic characteristics of the purified $\alpha$-amylase (F-2A) of Bacillus circulans F-2 and the digestion rate of various starches. 1. The molecular weight was estimated to be 93000 by SDS-polyacrylamide disc gel electrophoresis. The isoelectric point was about pH 5.0. The optimum pH for the enzyme action was 6.0-6.5 and the stable pH ranged pH 5.5-12.0. The optimum temperature was 6$0^{\circ}C$, and the purified $\alpha$-amylase was stable below 4$0^{\circ}C$. 2. The purified $\alpha$-amylase was activated by Mn$^{＋＋}$ and Co$^{＋＋}$, whereas it was inhibited by Ag$^{＋}$, HT$^{＋＋}$, Cu$^{＋＋}$ and Pb$^{＋＋}$. 3. The purified $\alpha$-amylase is considered to have no sulfhydryl residue essential for its catalytic activity. 4. Michaelis constant (Km) was 1.704 mg/$m\ell$. Activation energy between 25-4$0^{\circ}C$ was 12.297 Kcal/mole, and between 40-6$0^{\circ}C$, it was 7.831 Kcal/mole. 5. The hydrolysis product from soluble starch, amylose and amylopectin in the early stage of hydrolysis was G$_{6}$, and as hydrolysis proceeds, G$_4$and G$_2$appeared. 6. Products from each oligosaccarides are as follows: G$_4$longrightarrow G$_2$＋ G$_2$,G$_3$ ＋G$_1$,G$_{5}$longrightarrow G$_4$＋G$_1$,G$_{6}$longrightarrowG$_4$＋ G$_2$,G$_{7}$ G$_4$,G$_{8}$longrightarrow G$_4$＋G$_4$, 7. On raw potato starch, raw sago starch and raw yam starch, the purified enzyme exhibited a remarkably high digestion rate than Porcine pancreatic amylase and Streptococcus bovis amylase.
Bacillus circulans F-2의 정제$\alpha$-amylase(F-2A)의 효소적특성과 각종 생전분의 분해율을 검토하고 다음과 같은 결과를 얻었다. 1. 분자양은 93,000, 등전점은 pH5.0부근, 최적pH는 6.0~6.5, 안정 pH범위는 5.5~12.0, 최적온도는 6$0^{\circ}C$, 4$0^{\circ}C$ 이하에서 안정하였다. 2. Mn$^{＋＋}$, Co$^{＋＋}$ 은 부활제로써 작용하였으나 Ag$^{＋}$, Hg$^{＋＋}$, Cu$^{＋＋}$은 저해제로써 작용하였다. 3, 본 효소의 활성에 SH기는 필수적이 아닌 것으로 생각된다. 4. Michaelis constant (Km)는 1.704 mg/$m\ell$ 이고 활성화에너지는 25~4$0^{\circ}C$ 에서 12.297 kcal/mole, 40~6$0^{\circ}C$ 에서 7.831kca1/mo1e이었다. 5. Soluble starch, Amylose, Amylopectin으로부터 생성되는 초기분해산물은 G$_{6}$이며 분해가 진행됨에 따라 G$_4$와 G$_2$가 생성되었다. 6. 각종 Oligosaccharide로부터 생성되는 분해산물은 다음과 같다. G$_4$$\longrightarrow$ G$_2$＋ G$_2$,G$_3$ ＋G$_1$,G$_{5}$$\longrightarrow$ G$_4$＋G$_1$,G$_{6}$$\longrightarrow$G$_4$＋ G$_2$,G$_{7}$ G$_4$,G$_{8}$$\longrightarrow$ G$_4$＋G$_4$, 7. 감자 생전분, Sago 생전분, Yam 생전분에 대하여 본효소는 Porcine pancreatic amylase와 Streptococcus bovis amylase보다 월등하게 높은 분해율을 나타내었다.