通过ＲＮａｓｅ Ａ的水合等温线， 确定ＲＮａｓｅ Ａ吸附水时所处的相对湿度及其水合值的关系； 将标记上自旋探针（马来酰亚胺氮氧自由基） 的ＲＮａｓｅ Ａ溶液经透析后冷冻干燥并装入样品管后， 在不同相对湿度下与水相互作用， 待吸附平衡后将样品管密封测其ＥＳＲ波谱， 找出谱图上的Ａｍａｘ与ＲＮａｓｅ Ａ 水合值的关系； 从而建立了含微量水的ＲＮａｓｅ Ａ 分子运动与其水含量关系的检测方法， 得到导致ＲＮａｓｅ Ａ分子开始运动的最低水含量阈值约为每克干酶含水０．２０ ｇ， 即当１ 个ＲＮａｓｅ Ａ 分子周围有约１５２ 个水分子时ＲＮａｓｅ Ａ分子开始运动。 Through the hydration isotherms of RNase A, the relationship between the relative humidity and the hydration value of RNase A adsorbed water was determined. The RNase A solution labeled with spin probe (maleimide nitroxide) After freeze-drying and loading into the sample tube, it interacts with water at different relative humidity. After absorbing the equilibrium, the sample tube is hermetically sealed to measure its ESR spectrum, and the relationship between the Amax and RNase A hydration values ​​on the spectrum is found. The detection method of the relationship between the movement of RNase A molecules and the water content of trace water resulted in the lowest water content threshold of RNase A molecules about 0.20 g per gram of dry enzyme, RNase A molecules begin to move about 152 water molecules.