阳离子双子表面活性剂诱导的α-CT超活性和构象变化（英文）

发布时间：2018-10-22 15:30

【摘要】：报道了α-糜蛋白酶(α-CT)催化活性及其与阳离子双子表面活性剂(N,N′-双(十二烷基二甲基)-1,2-二溴化癸二铵,简写为12-10-12)相互作用热力学的关系。酶活性通过紫外-可见吸收光谱法测量底物醋酸2-萘酯(2-NA)分解速率进行评估。在较短的培育时间内,12-10-12能够激活α-CT,得到催化2-NA分解的超活性,同时也加速了酶变性的动力学过程。在低于α-CT/12-10-12体系的临界聚集浓度(cac12-10-12,CT)时,显示一个钟形的大的超活性区。酶活性随时间变化的结果表明,由12-10-12激活的α-CT有高的酶活性和低的变性稳定性。进而采用等温滴定量热(ITC)、稳态荧光光谱和差示扫描量热(DSC)技术研究了12-10-12诱导α-CT超活性的机理。结果表明酶的超活性来源于正电荷的12-10-12与α-CT相互作用对α-CT内部结构的扰动,使得酶的构象变得比处于弱相互作用平衡的天然酶的构象更加松弛,这有利于2-NA水解酸性产物释放的动力学,而同时也导致了α-CT结构的不稳定性。
[Abstract]:The catalytic activity of 伪-chymotrypsin (伪-CT) and the relationship between 伪-chymotrypsin (伪-chymotrypsin) activity and the interaction thermodynamics of cationic Gemini surfactants (N- (dodecyl dimethyl)-1 (dodecyl dimethyl)-1 + 2-dibromodecylammonium) (12-10-12) are reported. The enzymatic activity was evaluated by UV-vis absorption spectrometry to measure the decomposition rate of substrates 2-naphthalene acetate (2-NA). In a short incubation time, 12-10-12 can activate 伪-CT, to catalyze the decomposition of 2-NA and accelerate the kinetic process of enzymatic denaturation. Below the critical aggregation concentration (cac12-10-12,CT) of 伪-CT/12-10-12 system, a large bell-shaped superactive region is shown. The results showed that 伪-CT activated by 12-10-12 had high enzyme activity and low denaturation stability. The mechanism of 伪-CT superactivity induced by 12-10-12 was studied by means of steady state fluorescence spectra and differential scanning calorimetry (DSC) techniques of isothermal drop quantitative thermal (ITC), and differential scanning calorimetry (DSC). The results show that the superactivity of the enzyme originates from the disturbance of the internal structure of 伪-CT by the interaction between 12-10-12 and 伪-CT, which makes the conformation of the enzyme more relaxed than that of the natural enzyme with weak interaction equilibrium. This is beneficial to the release kinetics of acidic products hydrolyzed by 2-NA, and also leads to the instability of 伪-CT structure.
【作者单位】：河南师范大学化学化工学院精细化学品绿色制造河南省协同创新中心绿色化学介质与反应教育部重点实验室;河南科技学院化学化工学院;
【基金】：supported by the National Natural Science Foundation of China(21273061,21573061) Scientific Research Project of Higher Education of Henan Province,China(17A150032)~~
【分类号】：O629.8;O647.2

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