Effect of aqueous solvent structure on protein functions and food properties.

水溶液是展示酶功能和食品特性的主要环境。在本研究中，研究了水溶液结构对酶功能和食品特性的影响。为此，我们引入参数α作为溶液结构的指标，它由下列方程确定：γ_W=αX_S^2+βX_S^3式中γ_W(=a_W/X_W；a_W，水分活度；X_W是水的活度系数，X_S是溶液的摩尔分数。溶菌酶、α-凝乳酶原A和醇脱氢酶的热稳定性受到参数α所代表的水溶液结构的强烈影响，可能是通过影响蛋白质分子的分子内疏水相互作用来实现的。对于醇脱氢酶、溶菌酶和α-半乳糖苷酶，酶的动力学也受到参数β所描述的水溶液结构的影响。在这种情况下，溶液结构通过影响分子间的疏水相互作用来影响酶-底物的亲和力，并研究了聚合物水溶液的力学性质与溶液结构的关系。

Aqueous solution is the major environment where enzyme functions and food properties are presented. In this research, the role of aqueous solution structure on enzyme functions and food properties was in vestigated. For this purpose, we introduced the parameter α, as an index of the solution structure, which was determined by the following equation :γ_W=αX_S^2+βX_S^3where γ_W (=a_W/X_W ; a_W, water activity ; X_W, molar fraction of water) is activity coefficient of water and X_S is molar fraction ofsolute.Thermal stabilities of lysozyme, α-chymotripsinogen A, and alcohlodehydrogenase were proved to be strongly affected by the aqueous solution structure represented by the parameter α probably through its effect on the intramolecular hydrophobic interaction for protein molecules.Enzyme kinetics were also affected by the aqueous solution structure described by the parameter α for alcoholdehydrogenase, lysozyme, and β-galactosidase. In this case, the solution structure affected the enzyme-substrate affinity through its effect on intermolecular hydrophobic interaction.The relationship between the mechanical properties of aqueous polymer solution and the solution structure was also investigated.