双酶酶解制备花生降血压肽的动力学研究

摘要

为解析碱性蛋白酶2709和胰蛋白酶依次酶解花生蛋白制备降血压肽的动力学过程,测定了不同底物浓度和加酶量务件下酶解液的水解度(DH),并采用DH=A+B×ln(t+C)拟合水解度随时间变化曲线,然后结合双底物顺序反应机理,推导动力学常数,建立动力学模型.结果表明,碱性蛋白酶2709和胰蛋白酶在45℃酶解反应动力学模型为r=109.157 3×[E.]×exp(-0.158 0×DH)和r’=(1.191 2×[E’.]+0.06)× exp[-0.485 2×(DH'-DH1)];碱性蛋白酶2709和胰蛋白酶的失活系数分别为17.452 7 min-1和0.598 4min-1.碱性蛋白酶2709的酶解程度影响胰蛋白酶酶解,碱性蛋白酶2709较胰蛋白酶更耐受花生蛋白体系.%To analyze the kinetic process of preparation of antihypertensive peptide from successively hydrolyzing peanut protein by alkali protease 2709 and trypsin,degree of hydrolysis(DH)of samples with various suhstrate concentrations and enzyme dosage was measured,the kinetic constant and equation were deduced according to the mechanism of bi-substrate sequential reaction and curves of DH versus time were fitted by DH=A+B× In(t+C).The results showed that kinetic models of alkali protease 2709 and trypsin at 45 ℃ were r=109.1573 × [Eo] ×exp(-0.1580×DH) and r'=(1.1912×[E'o]+0.06) × exp[-0.4852× (DH'-DH1)],respectively,and inactive constants were 17.4527 min-1 and 0.5984 min-1,respectively.The DH of alkali protease 2709 would influence the enzymolysis of trypsin,and the alkali protease 2709 is more stable than trypsin under peanut protein system.