超声场对固定化木瓜蛋白酶的影响研究

Effect of ultrasonic treatment on immobilized papain

用壳聚糖-海藻酸钠固定化木瓜蛋白酶后,超声处理固定化酶能够提高其活力,但对其最适温度与最适pH没有影响。研究了超声温度、超声时间、超声频率及超声强度对固定化酶活力的影响,单因素实验表明,在水浴温度50℃,135kHz,0.45W/cm2条件下超声50min时,酶活力提高最为显著,较未经超声处理的固定化木瓜蛋白酶活力提高了25.85%。研究低频槽式超声处理的固定化酶的动力学,结果显示超声处理使Km值降低,与未经超声处理的固定化木瓜蛋白酶Km值相比下降了31.83%,接近游离酶的Km值,Vmax值升高了8.35%。结果表明,超声场使酶与底物的亲和力增加。

Chitosan-sodium alginate immobilized papain activity was enhanced by ultrasonic treatment,while the optimal temperature and the optimal pH were not influenced by the treatment. Effect of ultrasonic temperature, ultrasonic treating time,ultrasonic frequency and power on immobilized papain activity was studied. Result of single-factor experiment showed that treating the immobilized papain by 50℃, 135kHz,0.45W/cm2 ultrasonic for 50min could increase the papain activity most. Immobilized papain activity was enhanced by 25.85% in comparison to the untreated immobilized papain activity. Research on enzyme kinetics of free papain and immobilized papain showed that Km decreased by 31.83% after immobilized papain treated by ultrasonic. Vmax raised 8.35% of the untreated immobilized papain. This result provided the evidence that ultrasonic treatment could raise the affinity of enzyme and substrate.