【摘要】 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．更多还原

【Abstract】 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.更多还原