耐热醋酸棱状芽孢杆菌中具有高的二硫键还原活性组分的提取和特性研究

Isolation and Characterization of Active Components with High Disulfide Reduction Activity from Clostridium thermoaceticum

用ＤＥＡＥ－ＳｅｐｈａｒｏｓｅＣＬ－６Ｂ层析柱从Ｃ．ｔｈｅｒｍｏａｃｅｔｉｃｕｍ细胞提取物中分离出的两个具有相近分子量（７００）的活性组分，在ＭＶ＋存在下，对二硫键具有高的催化还原活性．这两组分参与的催化还原反应不以ＮＡＤ（Ｐ）Ｈ为电子供体．在实验条件下，对二硫键的催化还原活性顺序为：ＧＳＳＧ＞硫辛酰胺＞胱氨酸＞硫辛酸．活性组分具有较高的反应稳定性和热稳定性．两组分在２６０、３５４和５０５（４６５）ｎｍ处具有特征吸收峰．

Two active components with simliar molecular weight(about 700)were isolated by DEAE Sepharose CL 6B column from C.thermoaceticum ,which possessed high catalytic activity for the disufide bond reduction in the presence of reduced methyl viologen.However,the activity was not dectectable in the presence of NAD(P)H.The catalytic activity was proved by the product analysis and a long time Fed Batch assay.The sequence of substrates for the reduction activity was:GSSG>lipoamide>cystine>lipoic acid.The isolated active components possessed high reaction stability and high thermostability,and their characteristic absorption peak existed at 260,354 and 505(465)nm.