Hekmat Dariusch, Hebel Dirk, Joswig Sebastian, Schmidt Michael, Weuster-Botz Dirk
Institute of Biochemical Engineering, Munich University of Technology, Boltzmannstr. 15, 85748, Garching, Germany.
Biotechnol Lett. 2007 Nov;29(11):1703-11. doi: 10.1007/s10529-007-9456-9. Epub 2007 Aug 1.
The application of five water-soluble, halogen-free, alkylammonium-based ionic liquids (ILs) as additives for advanced crystallization of lysozyme was investigated. Their biocompatibility was determined by long-term measurement of the overall mean relative enzyme activities. These were maximally reduced by about 10-15% when up to 200 g IL l(-1) was added. Sitting-drop vapor diffusion crystallization experiments revealed that the addition of some of the ILs led to less crystal polymorphism and precipitation was avoided reliably even at larger NaCl concentrations. The addition of ILs tended to result in larger crystals. The kinetics of lysozyme crystallization were significantly enhanced using ILs as crystallization additives, e.g. by a factor of 5.5 when 100 g ethanolammonium formate l(-1 )was added. ILs with "soft" anions, such as formate or glycolate, were superior to ILs with "hard" anions, like nitrate.
研究了五种水溶性、无卤、基于烷基铵的离子液体（ILs）作为添加剂用于溶菌酶的高级结晶。通过长期测量总体平均相对酶活性来确定它们的生物相容性。当添加高达200 g IL l(-1)时，这些活性最大降低约10 - 15%。坐滴气相扩散结晶实验表明，添加某些离子液体可减少晶体多晶型现象，并且即使在较高的NaCl浓度下也能可靠地避免沉淀。添加离子液体往往会产生更大的晶体。使用离子液体作为结晶添加剂时，溶菌酶结晶的动力学显著增强，例如，添加100 g甲酸乙醇铵l(-1)时增强了5.5倍。具有“软”阴离子（如甲酸根或乙醇酸根）的离子液体优于具有“硬”阴离子（如硝酸根）的离子液体。
