Studies on $\alpha$-amylase of Bocillus circulans F-2 (Part II) Enzymatic characteristics of the purified $\alpha$-amylase

These experiments were conducted to investigate the enzymatic characteristics of the purified -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, and the purified -amylase was stable below 4. 2. The purified -amylase was activated by Mn and Co, whereas it was inhibited by Ag, HT, Cu and Pb. 3. The purified -amylase is considered to have no sulfhydryl residue essential for its catalytic activity. 4. Michaelis constant (Km) was 1.704 mg/. Activation energy between 25-4 was 12.297 Kcal/mole, and between 40-6, it was 7.831 Kcal/mole. 5. The hydrolysis product from soluble starch, amylose and amylopectin in the early stage of hydrolysis was G, and as hydrolysis proceeds, Gand Gappeared. 6. Products from each oligosaccarides are as follows: Glongrightarrow G＋ G,G ＋G,Glongrightarrow G＋G,GlongrightarrowG＋ G,G G,Glongrightarrow G＋G, 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.