Wusteman F S, Davidson E A
Connect Tissue Res. 1975;3(2):123-33. doi: 10.3109/03008207509152170.
Proteoglycan from pig costal cartilage and fragments obtained by proteolytic digestion were characterized by equilibrium ultracentrifugation and amino acid analysis. The proteoglycan extractable in 4 M guanidinium chloride yielded, after proteolytic digestion with trypsin and chymotrypsin, a chondroitin sulfate peptide containing four chains of polysaccharide. The unextractable residue yielded chondroitin sulfate peptide containing only two chains. The amino acid composition indicated a fairly uniform spacing between all four chains with an average of eight amino acid residues between the serine residues involved in linkage. Following the alkaline sulfite elimination-addition reaction, free peptide was isolated and found to contain one unsubstituted serine residue for every two linked glycosidically. Glycine and glutamic acid were the only two amino acids sufficiently abundant to be part of an invariant sequence near to serine residues destined to be glycosylated. The linkage region of the polypeptide also contains some substituted serine residues which do not carry a full chondroitin sulfate chain.
通过平衡超速离心和氨基酸分析对猪肋软骨蛋白聚糖及其经蛋白水解消化得到的片段进行了表征。用4M氯化胍可提取的蛋白聚糖在用胰蛋白酶和胰凝乳蛋白酶进行蛋白水解消化后，产生了一种含有四条多糖链的硫酸软骨素肽。不可提取的残留物产生了仅含两条链的硫酸软骨素肽。氨基酸组成表明所有四条链之间的间距相当均匀，参与连接的丝氨酸残基之间平均有八个氨基酸残基。经过碱性亚硫酸盐消除-加成反应后，分离出游离肽，发现每两个糖苷键连接的肽中含有一个未取代的丝氨酸残基。甘氨酸和谷氨酸是仅有的两种含量足够丰富的氨基酸，可成为注定要被糖基化的丝氨酸残基附近不变序列的一部分。多肽的连接区域还含有一些不携带完整硫酸软骨素链的取代丝氨酸残基。
