Study On Isolation And Purification Of α-amylase Inhibitor And Its Characteristics

A-amylase inhibitor is a great potential medicine, which can restrain the carbohydrate absorption in the digestive tract. It can effectively inhibit intestinal saliva and pancreatic amylase activity, and impede the hydrolysis and digestion of carbohydrates in food, reduce the intake of sugar, lower blood sugar and blood fat levels. It will not produce a high blood sugar after eating. Thus insulin secretion was reduced and fat synthesis was played down, weight loss. Currently it has a wide range of applications in medicine and agriculture, in clinical medicine it is used to prevent diabetes, high blood glucose, hyperlipemia etc; in agriculture, it also can be used as insect-resistant gene to improve the plant resistance or made of biological pesticides. In addition, in the enzyme research, it can be used as exploreα-amylase site analysis tools, as a determinationα-amylase reagent by selecting process. Therefore, there are very broad application prospects inα-amylase inhibitor.In this experimentα-amylase inhibitor was extracted from the wheat bran and t white kidney beans,and the technology was researched. The results showed that wheat bran : water = 1:8. The final choice of soaking time was 2h, 0.2mol/L NaCl helped the solution, and 70 percent of the ammonium sulfate precipitation, by the ultrafiltration membrane and freeze-drying processing, and got 2.072g powder sample, the total protein content was 201mg, specific activity was 103U/mg, the total inhibit vitality reached 20720U, recovery was 41.74%. It was stable between pH4-11;under 80 degrees Celsius in 30min, the activity ofα-amylase inhibiter got 10% loss;white kidney bean : water = 1:8. The final choice of soaking time was 24 h, 0.2mol / L NaCl helped the solution, to sulfate precipitation with 1:1 alcohol, eventually got 1.84g powder sample, specific activity was 22.2U / mg, the total inhibit vitality reached 33488U, recovery was 71.9%. It's stability in pH3-10, it was stable under 80 degrees Celsius.We got three bands fromα-AI of wheat bran by SDS PAGE. the moleculars were 33kD,30kD and 26kD;two bands were got from white kidney bean, he molecular were 35kD and 30kD. The inhibition kinetics showed the type ofα-AI of wheat bran was mixed non-competitive inhibition,the constant of inhibition (Ki) was 3.47mg/ml. the inhibition of white kidney beanα-AI was non-reversible.We also maked the experiment of large-scale extraction from wheat bran, gived the basic date for industry production.