萝卜块根中两个具溶菌酶活性的几丁质结合蛋白的纯化及其特性

通过亲和层析和羧甲基一纤维素离子交换层析从萝卜的块根中分离到两个具溶菌酶活性的酶组份：CBP1和CBP2。两者经SDS-PAGE均显示单一蛋白染色条带，其对应的分子量分别为26．9kD和24．8kD。两种蛋白除有溶菌酶活性外，还有几丁质酶活性，但无壳聚糖酶活性。各种类型的几丁质对CBP1和CBP2都有较强的吸附作用，而在还原／非还原的单向SDS-PAGE中却观察不到两者分子中存在二硫键。

Purification and Characterization of Two Chitin-binding Proteins with Lysozyme Activity from Roots of Raphanus sativus

A group of chitin-binding proteins were isolated from tuberous roots of Raphanus sativus by affinity chromatography with deaminated regen- erated chitin (Fig.1). SDS-PAGE showed that there are at least five proteins in the sample (Fig.2-b). T hr ough car boxyl m et hyl- cel l ul ose chromatography, two chitin-binding proteins with lysozyme activity, named as CBP1 and CBP2 (Fig. 3), were purified to homogeneity with the molecu- lar weights of 26.9 kD and 24.8 kD respectively (Fig.2-d, e). CBP1 and CBP2 were found to be bi- functional enzymes with activities of lysozyme and chitinase (Figs.4, 5), but without chitosanase activity (Table 1). The CBP1 and CBP2 could bespecifically absorbed by various forms of chitin, such as powdered, regenerated and colloidal forms chitin (Fig.6). No disulfide bridge was observed in CBP1 and CBP2 by reduced/nonreduced one- dimensional SDS-PAGE (Fig.7).