Chen C H, Kao O H, Berns D S
Biophys Chem. 1977 Jun;7(1):81-6. doi: 10.1016/0301-4622(77)87018-x.
Denaturation of the protein phycocyanin in urea solution was investigated by microcalorimetry, ultraviolet and visible spectroscopy, circular dichroism and sedimentation equilibrium. The results consistently demonstrated that in the presence of 7 M urea this protein is completely denatured. By assumings a two-state mechanism, an apparent free energy of unfolding at zero denaturant concentration, (formula: see text) was found to be 4.4 kcal/mole at pH 6.0 and 25 degrees C. By microcalorimetry the enthalpy of denaturation of phycocyanin app was found to be -230 kcal/mole at 25 degrees C. The relatively large negative enthalpy change results from protein unfolding and changes in protein solvation.
通过微量量热法、紫外可见光谱法、圆二色光谱法和沉降平衡法研究了藻蓝蛋白在尿素溶液中的变性情况。结果一致表明，在7M尿素存在下，这种蛋白质会完全变性。假设为两态机制，在pH 6.0和25℃时，零变性剂浓度下的表观解折叠自由能（公式：见原文）为4.4千卡/摩尔。通过微量量热法发现，藻蓝蛋白在25℃时的变性焓为-230千卡/摩尔。相对较大的负焓变是由蛋白质解折叠和蛋白质溶剂化变化引起的。
