带电蛋白质对α-淀粉酶活性及酶促反应的影响

Effect of charged protein on enzymatic activity of α-amylase and enzymatic reaction

利用Zeta电位仪对带电蛋白质表面的Zeta电位进行测量,在不同浓度梯度的还原型谷胱甘肽、牛血清蛋白和两种蛋白的混合溶液中分别加入α-淀粉酶,测定目标酶系的活性、米氏常数、活化能等参数。结果表明,分别加入浓度为0.6mmol/L还原型谷胱甘肽、牛血清蛋白和两种蛋白的混合溶液的酶活力分别提高7.9%、8.7%、11.1%,米氏常数从129.7g/L分别降低至116.0、104.2、85.1g/L,最大反应速率从32g/(L·min)分别降至30.50、28.10、23.79g/(L·min),活化能从13.91kJ/mol分别降至10.00、9.91、9.88kJ/mol。这种改变与蛋白质的浓度呈正相关,线性关系良好。说明不同带电蛋白质的加入使α-淀粉酶的活性增大,酶与底物的亲和力增加,反应速率加快,效率更高。

Zeta potential was measured to study the effect of charged proteins onα-amylase and its enzymatic reaction.α-amylase solution was added into reduced glutathione(GSH),bovine serum albumin(BSA)and the mixture of two proteins with different concentrations.The activities,kinetic parameters and activation energies were determined.The results showed that the activities were increased by7.9%,8.7% and 11.1% respectively at the concentration of 0.6 mmol/L.The kinetic parameters of Km decreased from 129.7 g/L to 116.0,104.2,85.1 g/L,while Vmdecreased from 32 g/(L·min)to 30.5,28.1,23.7 g/(L·min),respectively.The activation energies decreased from 13.91 kJ/mol to 10.00,9.91 and 9.88 kJ/mol.The change inα-amylase is positively correlated with the protein concentration and has a good linear relationship.The results indicated that the activity ofα-amylase and the affinity of enzyme and substrate increased,the reaction rate was accelerated and the efficiency was improved.