碘-淀粉褪色光度法测定青霉素酶活性

目的 构建褪色光度法测定青霉素酶活性新体系。方法 碘与淀粉显蓝色,青霉素酶催化青霉素水解产物青霉噻唑酸与碘反应,吸光度A变化与青霉素酶活性有关联。结果 在5min内,酶促反应符合一级反应的特征,青霉素酶活性E(U/mL)在0～4U/mL范围内与△A呈良好的线性关系:△A=-0.1612+0.3264E(U/mL),r=0.9965,表观摩尔吸光系数ε=1.88×10⁵L/(mol·cm),检测限为0.11U/mL。结论 方法用于自制酶液酶活性测定,结果满意。

Determination of penicillinase activity by iodine-starch chromogenic system bleaching photometry

Objective To establish a new system for the determination of penicillin enzyme activity by bleaching photometry. Methods The quantitative reaction between penicillium thiazolic acid and iodine in iodine-starch chromogenic solution resulted in the decrease of absorbance A. Penicillin enzyme activity can be calculated according to △A. Results The enzymatic reaction was consistent with the characteristics of the first order reaction in 5min, within the range of 0~4U/mL. It showed a good linear relationship between △A and penicillinase activity. The linear regression equation was △A=-0.1612+0.3264E(U/mL), and the linear regression coefficient r was 0.9965. Apparent molar absorption coefficient of penicillin enzyme ε was 1.88×105L/(mol·cm). The limit of detection was 0.11U/mL. Conclusion The method could be used for the determination of penicillin activity in the enzyme solution and the result was