摘要
目的纯化羧肽酶原B突变体C383A并研究其酶学性质。方法用DEAE-FF离子交换树脂纯化C383A,测定其动力学参数,温度对酶活性的影响、温度稳定性、最适pH以及pH稳定性等酶学性质,并与野生型比较。结果纯化后获得高纯度突变体C383A,与野生型相比,催化效率及稳定性均有提高,但与底物的亲和力降低,随着温度的上升催化速率的增长率低于野生型。结论将重组羧肽酶原B第383位Cys突变为Ala可对酶的性质产生影响,与野生型比较,C383A提高了酶的催化效率及温度和pH稳定性。
Objective To study the purification and enzymatic property of procarboxypeptidase B（mutant C383A）.Methods The mutant C383A was purified by DEAE-FF Ion-exchange Chromatography.The kinetic parameters and enzymatic property of mutant C383A which were compared with that of wild-type procarboxypeptidase B were measured,including the effects of temperature on activity and stability of mutant C383A,the optimal pH and the stability of pH.Results Compared with the wild-type procarboxypeptidase B,the purified mutant C383A with a high purity had the enhanced catalytic efficiency and stability.However,the affinity between mutant C383A and substrate was decreased and the increase of catalytic rate was lower than that of the wild-type as the temperature rose.Conclusion Cys383 mutation to Ala can affect the property of procarboxypeptidase B.Compared with the wild-type,the mutant C383A has the enhanced catalytic efficiency and stability to temperature and pH.
出处
《食品与药品》
CAS
2010年第9期308-312,共5页
Food and Drug
关键词
重组羧肽酶原B
定点突变
纯化
酶学性质
recombinant procarboxypeptidase B
site-directed mutation
purification
enzymatic property
