限制性内切酶Bsp78I的化学修饰与动力学研究

限制性内切酶Bsp78I的化学修饰与动力学研究 STUDIES ON CHEMICAL MODIFICATION AND KINETICS OF RESTRICTION ENDONUCLEASE BSp78I 黄宁悟 1 first-author 邹国林 1 曹新文 1 朱汝璠 1 武汉大学生命科学学院 武汉大学生命科学学院 College of Life Sciences,Wuhan University College of Life Sciences,Wuhan University 从Ｂａｃｉｌｌｕｓｓｐｈａｅｒｉｃｕｓ７８菌中将Ｂｓｐ７８Ｉ纯化到均一程度．测得该酶对ｐＢＲ３２２ＤＮＡ的Ｋｍ值为２．６７×１０－８ｍｏｌ·Ｌ－１．用对氯汞苯甲酸、磷酸吡哆醛、２，３一丁二酮修饰该酶巯基、赖氨酸、精氨酸残基，结果表明这些基团均与该酶活性有关． Restriction endonuclease Bsp78 I from Bacillus sphaericus 78 has been isolated and purified. The purified enzyme was found to be homogeneous. Michaelis constant of theenzyme is 2. 67×10-8mol. L-1 （substrate is PBR322 DNA）. The role of specific amino acidresidues in Bsp78 1 was assayed by chemical modification. Sulfhydryl groups were modifiedwith p-chloromercuribenzoic acid, lysine residues with pyridoxal-5’ -phosphate and arginineresidues with 2, 3-butanedione. The results show that thase residues are related to activity ofBsp78 I. 限制性核酸内切酶 化学修饰 米氏常数 restriction endonuclease chemical modification Michaelis constant Q783.1 1996-02-01 2021-04-01 2