Fundermental study of lysozyme crystallization at high pressure

首先，我们使用氯化铵和氯化铯作为溶质，在高达300 MPa的压力下检查了用于溶解度测量的高压系统。溶解度的重现性为（]SY+-[）0.5%。另一方面，在0.1MPa下考察了溶菌酶溶解度测定的条件。并得到如下结果。(1)溶解度测量中溶菌酶的固态取决于溶质的初始浓度。这意味着溶菌酶的样品溶液应在低浓度下制备。(2)达到饱和的振荡时间很长。CsCl和NH_4Cl的溶解时间最多为1 ~ 2天，但需数周。结果表明：（1）沉淀速率随压力的增加而降低;（2）溶解度随压力的增加而增加，即，在0.1 MPa下为7 mg/ml至在200 MPa下为20 mg/ml。

First our high pressure system for the solubility measurement was checked up to 300 MPa using ammonium chloride and cesium chloride as solutes. The reproducibility of the solubility was (]SY+-[)0.5%. On the other hand, conditions of the solubility measurement of lysozyme were surveyed at 0.1 MPa. and get following results. (1) The solid state of lysozyme in the solubility measurement depends on the initial concentration of the solute. It means that sample solution of lysozyme should be prepared at low concentration. (2) Shaking time to attain to the saturation is very long. It takes several weeks though those for CsCl and NH4Cl are at most one or two days.Next the solubility was checked at high pressure up to 200 MPa. It is found that (1) rate of the precipitaion decreased with increasing pressure and (2) the solubility increased, i.e., 7 mg/ml at 0.1 MPa to 20 mg/ml at 200 MPa.