pH值、温度、底物浓度对L1型金属β-内酰胺酶活性的影响

Influence of pH, temperature and concentration of substrate on the activity of L1 metallo-β-lactamase

目的研究pH值、温度、底物浓度对L1型金属β-内酰胺酶活性的影响。方法将表达后的L1酶纯化,以亚胺培南为底物,分光光度法测定不同pH值和温度的酶活性及不同底物浓度下的酶反应初速度,观察不同pH值,温度及底物浓度对酶活性的影响。结果L1酶的最适pH为8.2,L1酶在40℃时活性最高。在亚胺培南浓度不超过30μmol/L时,反应初速度随底物浓度增加而呈线性增加,当底物浓度超过100μmol/L时,酶活性反而受抑,初速度明显下降。结论该结果对进一步研究该酶的结构及酶学特性有重要意义,并可为开发有效的L1金属β-内酰胺酶抑制剂提供理论指导。

Objective To investigate the influence of pH, temperature and concentration of substrate on the activity of L1 metallo-β-lactamase. Methods The activity of pure L1 β-lactamase was detected at different pH, temperature and concentrations of imipenem using spectrophotometer. Results The optimal pH and temperature of L1 was 8.2 and 40 ℃ respectively. When imipenem concentrations were less than 30 μmol/L, the initial velocity of reaction linearly increased following the increasing concentrations of substrate. When the substrate concentrations were above 100 μmol/L, the enzyme activity was conversely inhibited and the initial velocity of reaction decreased. Conclusion Our findings will be helpful for further study on the structure and characteristics of L1. The results of this study provide the theoretical guidance for the development of effective L1 metallo-β-lactamase inhibitors.