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测定了野生型卵清溶菌酶及其定点突变体Ｒ２１Ｅ、Ａ３ＩＶ、Ｉ５５Ｌ、Ｓ９１Ａ、Ｄ１０１Ａ、ＳＩＳ、ＳＶＳ、ＴＩＴ、ＴＶＳ（后者三个字母为该酶序列中第４０、５５、９１位的氨基酸残基，野生型为ＴＩＳ）在不同浓度脲溶液中的变性热力学参数和酶活性。稳定性自由能（ΔＧＴＨ２Ｏ）变化范围为１６．８６～２８．６７ｋＪ／ｍｏｌ，变性中点脲浓度（［Ｃ］１／２）为４．８９～６．２４ｍｏｌ／Ｌ。并对这个过程的可能机理，定点突变引起的过渡热力学参数的变化，及个别氨基酸残基取代伴随的体积和疏水标度的变化对蛋白质稳定性影响的机理进行了讨论。
The wild-type egg white lysozyme and its site-directed mutants R21E, A3IV, I55L, S91A, D101A, SIS, SVS, TIT and TVS were determined (the latter three letters are the amino acids at positions 40, 55 and 91 of the enzyme sequence Residues, wild-type TIS) in different concentrations of urea solution denaturation thermodynamic parameters and enzyme activity. The range of variation of free radical energy (ΔGTH2O) was 16.86 ~ 28.67kJ / mol, and the concentration of urea ([C] 1/2) was 4.89-6.24mol / L. The possible mechanism of this process, the change of transition thermodynamic parameters caused by site-directed mutagenesis, and the mechanism of protein stability affected by the change of volume and hydrophobic scale accompanied by substitution of individual amino acid residues were discussed.