Kovrigin E L, Potekhin S A
Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142292 Russia.
Biochemistry. 1997 Jul 29;36(30):9195-9. doi: 10.1021/bi9630164.
On the basis of scanning microcalorimetry data from literature and our own measurements, we have calculated the changes in preferential solvation of lysozyme upon heat denaturation in six solvent systems: water + methanol, ethanol, propanol [data from Velicelebi, G., & Sturtevant, J. M. (1979) Biochemistry 18, 1180], acetone, p-dioxane [data from Fujita, Y., & Noda, Y. (1983) Bull. Chem. Soc.Jpn. 56, 233], and dimethylsulfoxide [our data Kovrigin, E. L., Kirkitadze, M. D., & Potekhin, S. A. (1996) Biofizika 41, 549-553; Kovrigin, E. L., & Potekhin, S. A. (1996) Biofizika 41, 1201-1206]. These preferential solvation changes are (in effect) the numbers of cosolvent molecules entering or leaving the solvation shell of the protein upon denaturation. It has been shown that for a group of five substances in the initial activity range (approximately up to 0. 3) the denaturational changes of preferential solvation of lysozyme do not depend on the nature of the solvent and depend only on its activity. This suggests that lysozyme does not distinguish these substances in the initial activity range and preferential solvation has a nonspecific character. It has been shown also that preferential solvation DeltaGamma23 does not depend on the pH value at least for dimethylsulfoxide-water solutions. This indicates that the chargeable groups exposed on denaturation do not contribute significantly to preferential interaction of the protein surface with the solution components.
基于文献中的扫描量热法数据以及我们自己的测量结果，我们计算了溶菌酶在六种溶剂体系中热变性时优先溶剂化作用的变化：水 + 甲醇、乙醇、丙醇[数据来自Velicelebi, G., & Sturtevant, J. M. (1979) Biochemistry 18, 1180]、丙酮、对二氧六环[数据来自Fujita, Y., & Noda, Y. (1983) Bull. Chem. Soc. Jpn. 56, 233]和二甲基亚砜[我们的数据Kovrigin, E. L., Kirkitadze, M. D., & Potekhin, S. A. (1996) Biofizika 41, 549 - 553; Kovrigin, E. L., & Potekhin, S. A. (1996) Biofizika 41, 1201 - 1206]。这些优先溶剂化作用的变化实际上是变性时进入或离开蛋白质溶剂化壳层的共溶剂分子数。已经表明，对于一组在初始活性范围内（大约高达0.3）的五种物质，溶菌酶优先溶剂化作用的变性变化不取决于溶剂的性质，仅取决于其活性。这表明溶菌酶在初始活性范围内不区分这些物质，并且优先溶剂化具有非特异性特征。还表明优先溶剂化ΔΓ23至少对于二甲基亚砜 - 水溶液不取决于pH值。这表明变性时暴露的可充电基团对蛋白质表面与溶液成分的优先相互作用没有显著贡献。
