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首先对影响葡萄糖磷酸变位酶（ＰＧＭ）稳定性的因素进行了比较研究，结果发现，在所有被检测的因子中，磷酸根对酶的保护作用最强，而Ｔｒｉｓ－盐酸则效果极差。在磷酸缓冲液中添加二硫苏糖醇、ＰＭＳＦ、葡萄糖和镁离子等可能的保持试剂未能进一步提高酶的稳定性。另外，ｐＨ对ＰＧＭ酶的稳定性有较大影响，酸性ｐＨ不利于酶活性的保持，在ｐＨ８．０时酶最为稳定。因此，本实验对ＰＧＭ同工酶的纯化均在ｐＨ８．０的磷酸缓冲液中进行。依次经过抽提、分步硫酸铵沉淀、ＳｅｐｈａｄｅｘＧ７５柱层析以及二乙氨乙基纤维素柱高效液相色谱（ＤＥＡＥ－ＨＰＬＣ）等分离步骤，我们纯化了大白菜品种“白阳”黄化种苗中的３个葡萄糖磷酸变位酶（ＰＧＭ）同工酶，并分别测定了同耐热相关ＰＧＭ同工酶和与其自然电泳迁移率相近的另一同工酶的米氏常数（Ｋｍ），比较了它们对３７℃热处理的稳定性。结果表明，在米氏常数和热稳定性方面它们没有显著差别，因而推测ＰＧＭ酶本身可能不是影响大白菜耐热性的主要因素
First of all, the factors influencing the stability of PGM were compared. The results showed that phosphate had the strongest protective effect on all the tested elements, while Tris-HCl showed very poor protection. The possible retention of reagents such as dithiothreitol, PMSF, glucose and magnesium ions in phosphate buffer failed to further increase enzyme stability. In addition, pH has a greater impact on the stability of PGM enzyme, acidic pH is not conducive to the maintenance of enzyme activity, the enzyme is the most stable at pH8.0. Therefore, in this experiment, the purification of PGM isozymes was carried out in phosphate buffer pH8.0. Followed by extraction, step-by-step ammonium sulfate precipitation, SephadexG75 column chromatography and diethylaminoethyl cellulose column high performance liquid chromatography (DEAE-HPLC) and other separation steps, we purified the Chinese cabbage varieties “white Yang” yellow Three glucose phosphoglucomutase (PGM) isozymes in seedlings were determined and the Michaelis constants (Km) of the same isozymes with heat-related PGM isoenzymes and with their similar natural electrophoretic mobility were determined, respectively Their stability to 37 ° C heat treatment. The results show that there is no significant difference in the Michaelis constant and the thermal stability, so it is speculated that the PGM enzyme itself may not be the main factor affecting the heat tolerance of Chinese cabbage