基于动力学分析β-伴大豆球蛋白和大豆球蛋白抑制淀粉酶活性机制

Mechanism of inhibitory on porcine pancreatic α-amylase activity by β-conglycinin and glycinin based on kinetic analysis

中文关键词:  β-伴大豆球蛋白  大豆球蛋白  猪胰α-淀粉酶  抑制动力学

英文关键词:β-conglycinin  glycinin  porcine pancreatic α-amylase  inhibition kinetics

中文摘要:

      目的 探讨β-伴大豆球蛋白(β-conglycinin, 7S)和大豆球蛋白(glycinin, 11S)对猪胰α-淀粉酶(porcine pancreatic α-amylase, PPA)的抑制动力学特征。方法 通过测定半抑制浓度(half maximal inhibitory concentration, IC50), 结合Cornish-Bowden方程和Dixon方程, 对7S和11S对PPA的抑制类型及抑制作用进行阐述。结果 7S对PPA的抑制作用属于混合型竞争性抑制, 而11S对PPA抑制作用主要是竞争性抑制。7S和11S的竞争性抑制常数(competitive inhibition constants, Kic)分别为3.958 mg/mL和37.083 mg/mL, 7S的反竞争性抑制常数(uncompetitive inhibition constants, Kiu)为37.394 mg/mL。7S的IC50值为49.771 mg/mL。7S的Kic比Kiu小, 这说明7S与游离的猪胰α-淀粉酶结合更密切, 而与淀粉和PPA形成的中间产物结合较为疏松。结论 7S和11S均通过抑制淀粉酶的活性来达到延缓淀粉类食品消化的目的, 而且7S对猪胰α-淀粉酶抑制作用更强。

英文摘要:

      Objective To investigate the inhibitory kinetic characteristics of porcine pancreatic α-amylase (PPA) by β-conglycinin (7S) and glycinin (11S). Methods The inhibitory types and effects of 7S and 11S on PPA were described by measuring the half maximal inhibitory concentration (IC50) and combining with Cornish-Bowden equation and Dixon equation. Results The inhibitory effect of 7S on PPA belonged to mixed competitive inhibition, while the inhibitory effect of 11S on PPA was mainly competitive inhibition. The competitive inhibition constants (Kic) of 7S and 11S were 3.958 mg/mL and 37.083 mg/mL, respectively, and the uncompetitive inhibition constants (Kiu) of 7S was 37.394 mg/mL. The IC50 value of 7S was 49.771 mg/mL. The Kic of 7S was smaller than that of Kiu, which indicated that 7S bound more closely to free porcine pancreatic α-amylase, but loosely bound to the intermediates formed by starch and PPA. Conclusion Both 7S and 11S achieve the purpose of delaying the digestion of starchy foods by inhibiting the activity of amylase, and 7S has a stronger inhibitory effect on porcine pancreatic α-amylase.