Choi H U, Meyer K
Biochem J. 1975 Dec;151(3):543-53. doi: 10.1042/bj1510543.
Quantitative structural comparisons were made between keratan sulphates isolated from various sources, namely pig nucleus pulposus, bovine cornea, and the costal cartilages of children, a young adult with Marfan syndrome and of old human autopsies. In human costal cartilage the amount of keratan sulphate increases markedly with age, although total mucopolysaccharide decreases to some extent, concomitant with a decrease in chondroitin 4-sulphate and an increase in chondroitin 6-sulphate. Comparison of molecular weights estimated by gel chromatography with those calculated from the molar ratio of galactose to mannose indicates that keratan sulphates of human costal cartilages of children and of a young adult with Marfan syndrome, and of pig nucleus pulposus, contain one mannose residue per chain, whereas keratan sulphates of old human costal cartilage and of bovine cornea contain one to two, and two, per chain respectively. After mild acid-catalysed desulphation of pig nucleus pulposus keratan sulphate, approx. 12% of the mucopolysaccharide aggregates irreversibly once the water is removed from the polysaccharide. The following conclusions have been drawn from a methylation analysis of keratan sulphates of various sources, aided by g.l.c.-mass spectrometry. (1) Fucose and N-acetylneuraminic acid are non-reducing terminal residues and the sialic acid is linked to the 3-position of galactose residues. (2) Pig nucleus pulposus keratan sulphate has approximately 4 non-reducing terminal groups per molecule and appears to be slightly less branched than the costal-cartilage keratan sulphate of children. The branching in human costal-cartilage keratan sulphates decreases with age. Bovine corneal keratan sulphate appears to be unbranched. (3) Mannose residues are linked by 3 different substituents in human costal-cartilage and bovine corneal keratan sulphates, and by two different substituents in pig nucleus pulposus keratan sulphate. (4) The sulphate ester groups are all on the 6-position of N-acetyl-glucosamine and galactose residues. The degree of sulphation increases with age in costal keratan sulphates with the increase mainly of the galactose 6-sulphate residues.
对从不同来源分离得到的硫酸角质素进行了定量结构比较，这些来源包括猪髓核、牛角膜以及儿童、患有马凡综合征的年轻成年人和老年人体检的肋软骨。在人类肋软骨中，硫酸角质素的含量随年龄显著增加，尽管总粘多糖在一定程度上有所减少，同时伴随着硫酸软骨素4 - 硫酸酯的减少和硫酸软骨素6 - 硫酸酯的增加。通过凝胶色谱法估算的分子量与根据半乳糖与甘露糖的摩尔比计算出的分子量进行比较表明，儿童、患有马凡综合征的年轻成年人的人类肋软骨以及猪髓核中的硫酸角质素，每条链含有一个甘露糖残基，而老年人类肋软骨和牛角膜中的硫酸角质素，每条链分别含有一到两个和两个甘露糖残基。猪髓核硫酸角质素经温和酸催化脱硫后，一旦从多糖中除去水分，约12%的粘多糖聚集体会不可逆地发生变化。借助气相色谱 - 质谱联用技术，对不同来源的硫酸角质素进行甲基化分析后得出了以下结论。（1）岩藻糖和N - 乙酰神经氨酸是非还原末端残基，唾液酸与半乳糖残基的3位相连。（2）猪髓核硫酸角质素每个分子约有4个非还原末端基团，其分支程度似乎比儿童肋软骨硫酸角质素略低。人类肋软骨硫酸角质素的分支程度随年龄降低。牛角膜硫酸角质素似乎没有分支。（3）在人类肋软骨和牛角膜硫酸角质素中，甘露糖残基通过3种不同的取代基相连，而在猪髓核硫酸角质素中通过两种不同的取代基相连。（4）硫酸酯基团都位于N - 乙酰葡糖胺和半乳糖残基的6位。肋软骨硫酸角质素的硫酸化程度随年龄增加，主要是半乳糖6 - 硫酸酯残基增加。
