凝乳酶热失活动力学研究

摘要

To study the thermal deactivation kinetics behavior of rennin,the Arrhenius equation was used to obtain the deactivating rate constant (k) and half-life (t1/2) at different temperatures (334 ～ 343 K).Then,the activation energy (Ea) of deactivated rennin was obtained,which was (539.58 ± 1.55) kJ/mol.When the temperature was in the range of 335 ～ 343 K,the deactivating rate constants could be well fitted with linear regression,which suggested that the deactivation of rennin was in accordance with the first-order kinetics model.At the lower temperature of 334 K,the curve of deactivating rate constant had lower linear fitting degree.The deactivating rate constant was on the high side at earlier stage but on the low side at later stage of heat preservation,and the curve slope was significantly different between earlier and later stages,which indicated that transition-state intermediate might be existent in the deactivation process of rennin.%为研究凝乳酶在334 ～ 343 K热失活动力学表现,利用Arrhenius方程,分别计算得到了不同温度下,凝乳酶的热失活速率常数k、半衰期t1/2,并最终计算得到了凝乳酶的失活活化能Ea为(539.58±1.55)kJ/mol.335 ～343 K时,数据线性回归拟合结果较好,凝乳酶的热失活符合一级反应动力学规律.在较低的334 K时,失活速率常数的线性回归分析拟合度较低,凝乳酶在保温前期失活速率常数偏高,而后期偏低,曲线斜率前后差别显著,提示凝乳酶的热失活可能存在中间过渡产物.