Liu Y, Sturtevant J M
Department of Chemistry, Yale University, New Haven, Connecticut 06511, USA.
Biochemistry. 1996 Mar 5;35(9):3059-62. doi: 10.1021/bi952198j.
The apparent change in heat capacity, delta C(p), accompanying the thermally induced unfolding of lysozyme and of ribonuclease A was determined by means of differential scanning calorimetry in dilute aqueous buffer containing one of the following added solutes: 0.5 M or 1.0 M sucrose, 1.0 M glycine, 0.5 M, 1.0 M, or 2.0 M guanidinium chloride, 10% glycerol, or 0.5 M NaCl over a pH range. In each system the temperature of half-completion, t1/2, of the unfolding transition was varied by varying the pH. The resulting enthalpies of denaturation were linearly dependent on t1/2 for each solvent system. The resulting values of delta C(p) for each protein showed variation of almost 2-fold. Such large variations in the sensitivity of the proteins to temperature changes are not readily interpreted.
通过差示扫描量热法，在含有以下添加溶质之一的稀水性缓冲液中，测定了溶菌酶和核糖核酸酶A热诱导去折叠过程中伴随的表观热容变化（ΔC(p)）：0.5 M或1.0 M蔗糖、1.0 M甘氨酸、0.5 M、1.0 M或2.0 M氯化胍、10%甘油，或在一定pH范围内的0.5 M NaCl。在每个体系中，通过改变pH来改变去折叠转变的半完成温度（t1/2）。对于每个溶剂体系，所得的变性焓与t1/2呈线性相关。每种蛋白质所得的ΔC(p)值显示出近2倍的变化。蛋白质对温度变化敏感性的如此大的变化难以解释。
