亚临界_超临界CO2处理对Pseudomonas cepacia脂肪酶活力和结构的影响.docVIP

 亚临界/超临界 CO2 处理对 Pseudomonas cepacia 脂肪酶活力和结构的影响# 陈大伟，刘云** 5 10 （华中科技大学生命科学与技术学院，武汉 430074） 摘要：本文探讨了亚临界/超临界 CO2 介质中压力、温度和时间对 Pseudomonas cepacia 脂肪 酶（PCL）活力和结构的影响。结果表明，在一定的压力和温度范围内，PCL 活力随压力和 温度的升高而增加，但是，处理时间对酶活力的影响较小。SDS分析显示，高压处理 不改变 PCL 的一级结构；CD 和荧光分析却表明，高压对 PCL 二级和三级结构影响较大。 亚临界（6MPa/35°C）处理对 PCL 活力的影响，主要是高压导致蛋白质二级结构α-螺旋和 β-折叠含量的变化，超临界（10MPa/40°C）处理对 PCL 活力的影响，则是由于蛋白质三 级结构的变化所致，从而阐明了亚临界/超临界处理对 PCL 酶活影响的机理。 关键词：亚临界/超临界 CO2；Pseudomonas cepacia 脂肪酶；酶活力；蛋白构象 中图分类号：TQ426.97 文献标识码： A 15 Effect of sub- and super-critical CO2 pretreatment on activity and structure of Burkholderia cepacia lipase Chen Dawei, Liu Yun (College of Life Science and Technology, Huazhong University of Science and Technology, 20 25 30 35 Wuhan 430074, China) Abstract: The effect of sub- and super-critical CO2 pretreatment on activity and structure of Burkholderia cepacia lipase (PCL) was studied, including pressure, temperatue and exposure time. Results showed that the PCL activity increased with the rising of pressure and temperature, but exposure time showed little effect. SDSanalysis showed that high pressure had no effect on the primary structure of PCL. However, CD and fluorescence analysis showed that high pressure had obvious effect on its secondary structure and tertiary structure. The activity variance of PCL treated in subcritical CO2 (6MPa/35°C ) pretreatment was mainly related to the secondary structure changes in alpha helix and beta folding content, while the activity variance of PCL treated in supercritical CO2 (10MPa/40°C) pretreatment depended on its tertiary structure changes. The results in this work are helpful to illustrate the mechanism of PCL activity variance in sub- and super-critical CO2. Key words: Sub-/super-critical CO2; Burkholderia cepacia lipase (PCL); Activity; Conformation 1. 前言 脂肪酶( EC 3. 1. 1. 3) 是一类具有特殊酯键水解能力的酶，广泛存在于动植物组织和微 生物中，广泛应用于食品、制革、饲料、洗涤、油酯化工、生物能源、有机合成和药物手性 拆分等领域 [1] 转酯、胺化、手性药物拆分等多种反应。研究表明[2]， PCL 是弱碱性酶，具有耐高温、耐 短链醇、以及宽广的 pH 和温度操作稳定性等优点，是目前催