Activity and thermal stability of lysozyme in alkylammonium formate ionic liquids-influence of cation modification
Activity and thermal stability of lysozyme in alkylammonium formate ionic liquids-influence of cation modification
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DOI：
10.1039/b900021f
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发表时间：
2009-01-01
期刊：
影响因子：
9.8
通讯作者：
Atkin, Rob
中科院分区：
文献类型：
--
作者：
Mann, Jason P.;McCluskey, Adam;Atkin, Rob
研究了4种质子型室温离子液体（甲酸乙铵（EAF）、甲酸丙铵（PAF）、甲酸2-甲氧基乙铵（MOEAF）和甲酸乙醇铵（EtAF））对鸡蛋白色溶菌酶的稳定性和活性的影响。近紫外CD实验已用于确定25重量%、50重量%和75重量%离子液体的水溶液中的蛋白质结构，并评估蛋白质在加热至90 ℃后再折叠的能力。确定EAF和MOEAF是类似有效的重折叠添加剂，而PAF在高达类似62.5wt%的浓度下更有效地促进重折叠，但在较高的PAF浓度下，蛋白质自发变性。这两种效应都归因于阳离子疏水性的增加。EtAF被证明可以稳定溶菌酶在高温下的解折叠，并且在冷却时复性似乎接近完成。酶动力学的研究表明，增加的蛋白质活性的存在下，所有的离子液体检查，但最显着的增加是注意到的EtAF，其中的速率是6倍高于那些确定的溶菌酶在缓冲水中。
The stability and activity of hen's egg white lysozyme in the presence of four protic room temperature ionic liquids (ethylammonium formate (EAF), propylammonium formate (PAF), 2-methoxyethylammonium formate (MOEAF) and ethanolammonium formate (EtAF)) have been investigated. Near UV CD experiments have been used to determine protein structure in aqueous solutions of 25 wt%, 50 wt% and 75 wt% ionic liquid, and to assess the proteins ability to refold after heating to 90 degrees C. It was determined that EAF and MOEAF are similarly effective refolding additives, while PAF is more effective at promoting refolding at concentrations up to similar to 62.5 wt%, but at higher PAF concentrations the protein spontaneously denatures. Both of these effects are attributed to the increased hydrophobicity of the cation. EtAF is shown to stabilise lysozyme against unfolding at high temperature, and renaturing appears to be near complete upon cooling. Studies of enzyme kinetics reveal increased protein activity in the presence of all ionic liquids examined, but the most significant increase is noted for EtAF, where rates are six times higher than those determined for lysozyme in buffered water.