Purification and structural characterization of a cartilage matrix protein.
Purification and structural characterization of a cartilage matrix protein.
复制标题
软骨基质蛋白的纯化和结构表征。
作者：
M. Paulsson;D. Heinegård
软骨基质蛋白是牛软骨中一种主要的非胶原蛋白。采用氯化铯-密度梯度离心法、凝胶层析和差示沉淀法，从牛气管软骨的5-M-氯化鸟苷提取液中分离纯化得到5-甲氧基-2-甲氧基异丙基吡啶。沉淀-平衡离心法测得完整蛋白的相对分子质量为148000。通过二硫键的还原，它被解离为三个亚基，分子量为52000。软骨基质蛋白在低盐溶液中不溶，在十二烷基硫酸钠/聚丙烯酰胺凝胶电泳法上表现异常。半胱氨酸含量较高，芳香氨基酸含量较低。碳水化合物含量为3.9%(w/w)。经木瓜酶消化后得到的糖肽在凝胶层析中呈异质性。天冬酰胺/天冬氨酸在纯化的糖肽中有丰富的存在，表明N-糖苷键与蛋白质有关。
The cartilage matrix protein is a major non-collagenous protein in bovine cartilage. It was purified from a 5 M-guanidinium chloride extract of bovine tracheal cartilage by sequential CsCl-density-gradient centrifugation, gel chromatography in guanidinium chloride and differential precipitation. The molecular weight of the intact protein is 148 000, determined by sedimentation-equilibrium centrifugation. It was dissociated to three subunits of molecular weight 52 000 by reduction of disulphide bonds. The cartilage matrix protein was insoluble in low-salt solutions and behaved abnormally on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The content of cysteine was high, whereas the contents of aromatic amino acids were low. The carbohydrate content was 3.9% (w/w). Glycopeptides obtained after papain digestion were heterogenous on gel chromatography. Asparagine/aspartic acid was enriched in the purified glycopeptides, indicating the presence of N-glycosidic linkages to protein.