阿卡波糖对胰α-淀粉酶的抑制动力学研究

Researches on Inhibition Kinetics of Pancreatic α-Amylase by Acarbose

为探究以马铃薯淀粉为底物时阿卡波糖对胰α-淀粉酶(来自猪胰)的抑制动力学,采用3,5-二硝基水杨酸显色法及双倒数作图法(Lineweaver-Burk法),体外模拟人体生理环境,建立胰α-淀粉酶最佳反应体系。结果显示,阿卡波糖在体外对胰α-淀粉酶活性具有明显的抑制作用,且作用效果随阿卡波糖浓度升高而增强,其半抑制浓度IC_(50)=5.975×10^(-6)mol/L,即3.854×10^(-3)mg/mL。通过双倒数作图法得知,胰α-淀粉酶的Km=12.309 mmol/L,阿卡波糖对胰α-淀粉酶的抑制类型为非竞争性与竞争性抑制混合型。本研究证实了以马铃薯淀粉为底物测定阿卡波糖对胰α-淀粉酶的抑制作用更为灵敏,为其它抑制剂以马铃薯淀粉为底物时抑制胰α-淀粉酶活性的研究提供了比较依据;且证实了阿卡波糖对胰α-淀粉酶有较强的抑制作用,可为临床治疗2型糖尿病时减少阿卡波糖的副作用提供一定的参考。

To explore the inhibitory kinetics of pancreatic a-amylase by acarbose using potato starch as substrate, human physiological environment in vitro was simulated and the optimal reaction system of pancreatic a-amylase was established. Experiments were measured by 3,5-dinitrosalicylie acid method and double-reciprocal plot （Lineweaver-Burk plot）. The re- suits showed that the activity of pancreatic a-amylase was inhibited by acarbose obviously, and the inhibition was enhanced with the increasing of acarbose concentration. The half inhibitory concentration （ IC50 ） was 5. 975- 10 -6 mol/L （ 3. 854 - 10 -3 mg/mL）. The double-reciprocal plot indicated that the Km of pancreatic a-amylase was 12. 309 mmol/L and the inhibition type is the hybird of noncompetitive and competitive inhibition. It was more sensitive to determine the inhibition effect of acarbose on pancreatic a-amylase when using potato starch as substrate, the results may provide the basis and comparisons for the inhibition research of pancreatic a-amylase activity by other inhibitors. Our research also confirmed that acarbose had a strong inhibitory effect on pancreatic a-amylase, which provide a reference for the reduction of side-effects of the use of acarbose in the clinical treatment of type 2 diabetes.