冬虫夏草菌中酸性非限制性DNA内切酶的研究  

A New Deoxyribonuclease was Found in a Fungus Cordyceps Sinensis

作　　者：夏服宝[1] 涂文娟[1] 黄旺[1] 彭文明[1] 

机构地区：[1]湖北工业大学生物工程学院,湖北武汉430068

出　　处：《湖北工业大学学报》2005年第1期11-13,共3页Journal of Hubei University of Technology

摘　　要：从冬虫夏草菌丝体中提取并纯化了一种酸性非限制性DNA内切酶,命名为CSDNase.CSDNase是通过(NH4)2SO4 沉淀, Sephacryl S 100 HR分子筛层析柱,DEAE Sepharose F.F离子交换和HPLC分离纯化得到的.在SDS PAGE电泳中CSDNase分子量约为34 kDa.CSDNase对超螺旋DNA(质粒),双链DNA(λDNA),单链DNA(鲑鱼精DNA)都有非特异性的内切酶活性,但CSDNase 不能消化RNA. CSDNase 在pH5.5的醋酸铵缓冲体系中处于最大DNase活性,最适反应温度为55 ℃.CSDNase酶活不依赖于金属离子,EDTA不能抑制其酶活,但高浓度的金属离子对酶活有明显的抑制作用.　An acid deoxyribonuclease (DNase) was isolated from the culturedmycelia of Cordyceps sinensis, designated CSDNase. CSDNase was purified by (NH4)2SO4precipitation, gel filtration of Sephacryl S-100 HR, weak anion-exchange HPLC and gel filtration HPLC. The protein was single-chained, with an apparent molecular mass of 34 kDa revealed by SDS-PAGE. CSDNase acted on both dsDNA and ssDNA, but acted preferentially on dsDNA. The optimum pH of CSDNase was approximately pH 5.5 and the optimum temperature was 55℃.The activity of CSDNase was not dependent on divalent cation, and EDTA also could not inhibit its enzyme activity. CSDNase hydrolyze DNA generating a terminus with 3′-phosphate and 5′-OH. These results indicated that the CSDNase was a member of the acid DNase family. It was the first time that an acid DNase was found in fungus.

关 键 词：冬虫夏草 内切酶 限制性 DEAE-Sepharose SDS-PAGE电泳 中酸性 (NH4)2SO4 超螺旋DNA 单链DNA DNASE 分离纯化 HPLC 离子交换 非特异性 缓冲体系 金属离子 反应温度 EDTA 抑制作用 菌丝体 层析柱 分子筛 分子量 醋酸铵 RNA 

分 类 号：Q783.1[生物学—分子生物学] S567.35[农业科学—中草药栽培]