Zhang Xiao-qi, Yang Ming-yan, Ma Yu, Tian Jia, Song Ji-Rong
Shaanxi Microbiology Institute, Xi' an 710043, China.
Yao Xue Xue Bao. 2007 Dec;42(12):1282-7.
An alpha-amylase inhibitor (alpha-AI) was isolated from white kidney beans (Phaseolus vulgaris L) by ethanol fractional precipitation, ion exchange chromatography and gel filtration column chromatography. It was a homogeneity glycoprotein demonstrated by SDS-PAGE and gel filtration on CL-6B. The glycoprotein contained 88.2% protein and was rich in aspartic acid, glutamic acid, leucine, threonine and serine. The carbohydrate moiety was consisted of Man, Glc, Gal and Xyl in a mole ratio of 2.42: 1.50: 1.52: 1.00. The glycan and the core protein backbone was connected by O-linkage as determined by beta-elimination reaction. The continuous oral administration of the alpha-AI (150 mg x kg(-1) x d(-1)) for 7 days can lower fasting blood glucose and 300 mg x kg(-1) x d(-1) alpha-AI for 7 days can improve the sugar tolerance on alloxan-dependent diabetic model rats. The result showed the alpha-AI obtained from white kidney beans had good hypoglycemic effect on alloxan induced diabetic rats and may have high potential pharmaceutical value as a regulative digestive-starch degradation in patients suffering from diabetes.
通过乙醇分级沉淀、离子交换色谱和凝胶过滤柱色谱从白芸豆（菜豆）中分离出一种α-淀粉酶抑制剂（α-AI）。经SDS-PAGE和CL-6B凝胶过滤证明，它是一种均一糖蛋白。该糖蛋白含88.2%的蛋白质，富含天冬氨酸、谷氨酸、亮氨酸、苏氨酸和丝氨酸。碳水化合物部分由甘露糖、葡萄糖、半乳糖和木糖组成，摩尔比为2.42:1.50:1.52:1.00。通过β-消除反应确定，聚糖与核心蛋白主链通过O-连接相连。连续7天口服α-AI（150 mg·kg⁻¹·d⁻¹）可降低空腹血糖，连续7天口服300 mg·kg⁻¹·d⁻¹α-AI可改善四氧嘧啶诱导的糖尿病模型大鼠的糖耐量。结果表明，从白芸豆中获得的α-AI对四氧嘧啶诱导的糖尿病大鼠具有良好的降血糖作用，作为调节糖尿病患者消化淀粉降解的药物可能具有很高的潜在药用价值。
