诺卡氏菌催化环氧琥珀酸水解反应的影响因素  

Factors Affecting the Epoxysuccinate Hydrolysis with Nocardia sp. Cells

作　　者：毛庆静[1] 谭小钉[1] 蔡水洪[2] 叶勤[1] 

机构地区：[1]华东理工大学生物反应器工程国家重点实验室,上海200237 [2]华东理工大学化学工程研究所,上海200237

出　　处：《华东理工大学学报（自然科学版）》2003年第3期264-267,共4页Journal of East China University of Science and Technology

基　　金：上海市重点学科项目部分资助

摘　　要：诺卡氏菌经超声波破碎后 ,环氧琥珀酸水解酶活性比完整细胞提高 40倍以上 ,表明细胞通透性对酶的表观活性影响很大。用顺式环氧琥珀酸二钠溶液处理诺卡氏菌细胞 ,可使细胞的通透性提高 ,表观环氧琥珀酸水解酶活增大 ,转化反应时间缩短。底物不存在时 ,诺卡氏菌细胞的环氧琥珀酸水解酶在 3 7°C不稳定 ,游离细胞的表观酶活半衰期为 1 9min,破碎细胞酶活仅 1 0 .4min,表明内源蛋白酶是造成破碎细胞环氧琥珀酸水解酶不稳定的重要原因。完整诺卡氏菌细胞于 3 7°C放置后再将细胞破碎 ,环氧琥珀酸水解酶的半衰期为 1 44 min,表明 3 7°C放置后细胞通透性受到较大影响。存在底物时完整诺卡氏菌细胞于 3 7°C放置后表观酶活基本不变。The epoxysuccinate hydrolase activity of Nocardia sp. increased by more than 40 times when the cells were disintegrated with ultrasonication, suggesting the permeability of the cells played an important role in the hydrolysis of epoxysuccinate. The apparent activity of epoxysuccinate hydrolase in intact cells of Nocardia sp. was elevated when the cells were pretreated with the substrate, cis epoxysuccinate, which resulted in a shortened reaction time. This was attributed to the improvement of permeability of the cells. In the absence of epoxysuccinate, the apparent and actual activity of epoxysuccinate hydrolase in intact and ultrasound treated cells decreased rapidly when exposed at 37 °C . The half life periods were 19 and 10.4 min respectively, suggesting the more rapid degradation of epoxysuccinate hydrolase by intracellular protease in the disintegrated cells occurred. When the activity of epoxysuccinate hydrolase was measured with the cells exposed at 37 °C then disintegrated with ultrasound, the half life period increased to 144 min, suggesting that the cell permeability decreased in the course of exposure to 37 °C . However, when the cells were incubated at 37 °C in the presence of epoxysuccinate, the apparent activity of epoxysuccinate hydrolase could be maintained.

关 键 词：诺卡氏菌 通透性 环氧琥珀酸水解酶 稳定性 L(+)酒石酸 

分 类 号：TQ921.7[轻工技术与工程—发酵工程]