English Name: α-Amylase (Bacillus subtilis); 1,4-α-D-Glucan-glucanohydrolase

Other Names: Medium-temperature amylase; Liquefying amylase; Liquefying enzyme; α-1,4-Dextrinase; Bacterial amylase; α-Amylase enzyme; Dextrinizing enzyme

CAS Number: 9000-90-2

Grade: BR

Activity: ≥4000 U/g or 50 U/mg protein

Activity Definition: One unit of enzyme activity (u/ml) is defined as the amount of enzyme that liquefies 1 gram of soluble starch per hour at 60°C and pH 6.0.

Moisture: ≤8%

Thermal Stability: Relatively stable below 60°C; optimal activity temperature is 60–70°C; can be used in liquefaction processes up to 90°C.

pH Stability: Relatively stable at pH 6.0–7.0; optimal pH is 6.0; severe inactivation occurs below pH 5.0.
Effect of Calcium Ion Concentration on Enzyme Activity: Calcium ions enhance the stability of enzyme activity; without calcium ions, enzyme activity is completely lost.

Appearance: Yellow-brown or off-white powder. Extracted from Bacillus subtilis, soluble in water. Under medium-temperature conditions, this enzyme rapidly hydrolyzes the α-1,4-glycosidic bonds in starch molecules, randomly cleaving starch molecules internally into short-chain dextrins of varying lengths and a small amount of low-molecular-weight sugars. Both amylose and amylopectin are decomposed in an irregular manner, rapidly reducing the viscosity of starch slurry (i.e., liquefaction; also known as liquefying enzyme). When stored at temperatures not exceeding 25°C, enzyme activity remains at no less than 90% of the labeled activity for six months. To enhance enzyme stability, calcium ion concentration should be no less than 50–70 ppm. Metal ions such as iron, copper, mercury, and zinc, as well as certain surfactants, may affect enzyme activity. If the liquefaction temperature is too low or the material concentration is too high, the enzyme dosage should be appropriately increased. Enzyme activity loss may occur if the material pH is above 8.0 or below 5.0.

Use: Biochemical research. Rapidly liquefies starch to produce low-molecular-weight compounds.

Storage: 2–8°C