变性剂作用下文昌鱼碱性磷酸酶构象与催化活力变化

Changes in Comformation and Catalytic Activity of Amphioxus Alkaline Phosphatase in Denaturants

研究了文昌鱼碱性磷酸酶(AKP)的变性作用,结果表明:低浓度盐酸胍(0.5 mol/l,1.0 mol/l)对该酶具有明显激活作用;酶的荧光构象变化指标随脲浓度增大呈现两个陡变区(1.0～2.0 mol/l,4.0～8.0 mol/l),蜂位因变性剂存在而明显红移,表明肽链己发生较明显的伸展,该酶的失活与变性过程均为一级反应,低浓度脲(2.0 mol/l)作用表现为构象变化略快于失活,而高浓度盐酸胍(2.0 mol/l,4.0 mol/l)及高浓度脲(4.0 mol/l,6.0 mol/l,8.0 mol/l)作用均表现为失活略快于构象变化。

The results of the AKP denaturation indicated that the. enzyme was activated at lower concentrations of Gu-HCl. The fluorescence data of the enzyme denatured by urea showed two changing areas (1. Omol/l-2. 0 mol/1 urea, 4. Omol/l-8. 0 mol/1 urea); the positions of emission peak also red shifted from 337. 2 nm to ,348 nm. The, process of AKP denaturation and inactivation by denaturants were both first-order reaction. The inactiyatipn rate of AKP in 2.0mol/I urea was slower than that of denaturation on the contrary in higher concentrations of Gu-HCl(2, 0mol/1,4. 0mol/1)and urea (4.0mol/1, 6. 0mol/1) ,the inactivation rate was faster than denaturation.