海蜇头糖蛋白基本组成及结构

摘要

A homogeneous Glycoprotein (JGP-Ⅲ) was isolated and purified from jellyfish oral-arms. The molecular weight of JGP-Ⅲ was estimated to be 109.7 ku by SDS-PAGE. JGP-Ⅲ contain 12.61% total suger,74.34 % protein, 8.47 % amide sugar,0.84 % uronic acid, 1.06 % sulfate group and 0.92 % sialic acid.Monosaccharides composition of JGP-Ⅲ was Rha, Fuc, Ara, Man, Glc, GalNAc, and GlcNAc determined by GC.Amino acid composition of JGP-Ⅲ was rich in glycine, valine, glutanmic acid, alanine, proline, methionine and asparagic acid, and lacking in histidine and tryptophan. The existence of O-glycosidic and N-glycosidic linkage in the glycoprotein was demonstrated with β-elimination reaction and peptide N-glycosidase F reaction. IR spectrum of JGP-Ⅲ indicated the strcture characterization of glycoprotein.%对海蜇头糖蛋白的基本组成和结构进行研究探讨.采用多步分离纯化方法获得电泳纯的海蜇头糖蛋白JGP-Ⅲ.经化学分析方法测定,JGP-Ⅲ中含有12.61%总糖,74.34%总蛋白,8.47%氨基糖,0.84%糖醛酸,1.06%硫酸根、0.92%唾液酸.JGP-Ⅲ的单糖组成主要有氨基葡萄糖,氨基半乳糖,葡萄糖,甘露糖,岩藻糖和鼠李糖.氨基酸组成中甘氨酸含量最高,其次为缬氨酸、谷氨酸、丙氨酸、脯氨酸、天门冬氨酸等,缺乏色氨酸和组氨酸.JGP-Ⅲ经消除反应前后紫外吸收和氨基酸组成的变化以及糖肽酶F作用后分子量的变化,表明JGP-Ⅲ中即有O-连接糖肽键的存在又有N-连接糖肽键的存在.通过红外光谱分析,发现JGP-Ⅲ具有糖蛋白的典型结构.