压力—温度协同作用下华根霉脂肪酶的催化行为研究

Study on catalytic behaviors of Rhizopus chinensis lipase under synergic action of high pressure and temperature

研究了高压处理中压力和温度对华根霉脂肪酶的活力和稳定性的影响,并利用活性酶变性酶的双态模型考察了酶的热变性,并构建压力—温度二元相图。研究结果表明:在0.1~200.0 MPa时,华根霉脂肪酶活力随压力提升而增加,其中在压力200 MPa时酶活达到最高值,是常压下初始酶活的116%;当压力超过200 MPa时,酶活开始降低,尤其在400~600MPa范围内迅速降低。压力—温度协同作用下华根霉脂肪酶的加工稳定性数据显示,在200 MPa、40℃下酶热稳定性最佳,压力超350 MPa时酶热稳定性显著降低。

The effects of pressure and temperature on the activity and the stability of Rhizopus chinensis lipase during high hydrostatic pressure treatment were studied.Based on the two-state model,the thermal denaturation of the enzyme was investigated and the isokineticity diagram was obtained.Within 0.1~200.0 MPa the enzyme activity increased with the pressure and the maximum activity was achieved at 200 MPa,which was 116% of that at atmospheric pressure.The activity began to decrease at pressure above 200 MPa and this tendency accelerated upon the pressure superior to 400 MPa.The high pressure treatment did not modify the optimal temperature of the enzyme.The enzyme exhibited the highest stability when it was treated at 200 MPa and 40℃.Its stability declined obviously when it was treated under pressure above 350 MPa.The above behavior could be explained by the isokineticity diagram.