[ Objective] To analyze the molecular structure of chitin-binding proteins (CBPs) with lysozyme activity, so as to provide the material for understanding the catalysis mechanism and physiology function of CBPs, [ Method ] CBPs were purified by affinity chromatography and cation exchange chromatography on a CM-cellulose column, and then the amino acid components, glycoprotein, and the active center of lysozyme activity were determined. [Result] There were two purified fractions from Raphanus sativus with lysozyme activity; CBP1 and CBP2, which were not glycoprotein. After modified by special modification agents, the lysozyme activity was inhibited notably, which could be pre-protected by GlcNAc, [Conclusion] It could be estimated that Asp/Glu and His were the catalytic center of CBP1 and CBP2 lysozyme activity.%[目的]分析萝卜具有溶菌酶活性组分CBPs的分子结构,以期为其作用机制和在萝卜中的生理功能提供资料.[方法]利用亲和层析法及CM-纤维素离子交换柱层析分离纯化CBPs,测定其氨基酸组成、糖基和溶菌酶活性中心残基.[结果]从萝卜中得到了2个具溶菌酶活性且无糖基的组分:CBP1和CBP2,它们间氨基酸组成差异不大；Asp/Glu和His专一性化学修饰剂单独作用后,CBP1和CBP2相对溶菌酶活力均大幅度降低,预先加入竞争性抑制剂则下降的幅度减小.[结论]萝卜中有2个具溶菌酶活性的非糖蛋白组分,其溶菌酶活性中心氨基酸残基均可能含有Asp/Glu和His.
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