Lyster R L
Department of Food Science and Technology, University of Reading, UK.
J Dairy Res. 1992 Aug;59(3):331-8. doi: 10.1017/s0022029900030600.
The three aspartic acid residues that form part of the Ca-binding site of mares' milk lysozyme have apparent pK values of 4.9, 4.3 and 4.1. The fluorescence of tryptophan has been used to compare the denaturation of mares' milk lysozyme by guanidinium chloride at various concentrations of Ca with that of hens' egg-white lysozyme (EC 3.2.1.17) and alpha-lactalbumin. Fluorescence revealed an intermediate stage in the denaturation of mares' milk lysozyme. The Ca-free form of mares' milk lysozyme is slightly more stable than that of alpha-lactalbumin, but its interaction with Ca is similar to that of alpha-lactalbumin, since only the native state binds Ca. Three-state models of denaturation can usefully be displayed on a ternary diagram.
构成马乳溶菌酶钙结合位点一部分的三个天冬氨酸残基的表观pK值分别为4.9、4.3和4.1。色氨酸的荧光已被用于比较在不同钙浓度下，氯化胍对马乳溶菌酶、鸡蛋清溶菌酶（EC 3.2.1.17）和α-乳白蛋白的变性作用。荧光显示马乳溶菌酶变性存在一个中间阶段。马乳溶菌酶的无钙形式比α-乳白蛋白略稳定，但其与钙的相互作用与α-乳白蛋白相似，因为只有天然状态能结合钙。变性的三态模型可以有效地显示在三元图上。
