小分子封闭提高固定化青霉素酰化酶的稳定性

Improvement for catalytic stability of immobilized penicillin acylase by blockage of small molecule reagents

为提高青霉素酰化酶的催化性能和热稳定性,在酶组装过程中添加小分子试剂对介孔泡沫硅载体表面过量的活化位点进行封闭。详细考察了小分子添加质量分数和种类对青霉素酰化酶负载率、催化活力及热稳定性的影响。实验结果得到:经精氨酸封闭的固定化酶活力提高至1.92倍;甘氨酸封闭的固定化酶5 h的50℃热稳定性提高至2.9倍,甘氨酸和谷氨酸封闭的固定化酶50℃热处理25 h仍保持87.9%和82.2%的残余活力;甘氨酸和谷氨酸封闭的固定化酶最适催化pH值向中性偏移且对pH值的耐受性增强。结果表明,在青霉素酰化酶共价组装过程中添加合适的小分子封闭能显著提高酶的催化性能和热稳定性。

In order to improve catalytic properties and thermal stability of penicillin acylase （PA）, small molecule reagents were assembled to quench the excessive active groups of mesoeellular siliceous foams （MCFs）. The effects of adding mass fraction and types of small molecule reagents on the coupled yield, the catalytic activity and thermal stability of PA were investigated. The activity of immobilized PA quenched by arginine is enhanced to 1.92 folds, and the thermal stability of immobilized PA preparation blocked by glyein is increased to 2.9 folds at 50℃ for 5 h. The residual activity of PA preparations of glycin and glutamic acid remain 87.9% and 82.2% , respectively, after treatment at 50 ℃for 25 h. The optimum pH of PA preparations of glyein and glutamie acid shifts to neutral, and their tolerance to pH is strengthened. The results indicate that the suitable blockage with small molecule reagents can improve the catalytic properties and thermal stability of PA assembled in MCFs.