Linker A
Biochem J. 1979 Dec 1;183(3):711-20. doi: 10.1042/bj1830711.
Oligosaccharides obtained from heparan sulphate by nitrous acid degradation were shown to be degraded sequentially by beta-D-glucuronidase or alpha-L-iduronidase followed by alpha D-N-acetylglucosaminidase. Structural analysis of the tetrasaccharide fraction showed the following. (1) N-Acetylglucosamine is preceded by a non-sulphated uronic acid residue that can be either D-glucuronic of L-iduronic acid, but followed by a glucuronic acid residue. (2) The N-acetylglucosamine in the major fraction is sulphated. (3) Very few if any of the uronic acid residues are sulphated (4). The results indicate that the area of the heparan sulphate chain where disaccharides containing N-acetylglucosamine and N-sulphated glucosamine residues alternate is higher in sulphate content than expected and that the sulphate groups are mainly located on the hexosamine units.
通过亚硝酸降解从硫酸乙酰肝素获得的寡糖被证明可依次被β-D-葡萄糖醛酸酶或α-L-艾杜糖醛酸酶降解，随后被α-D-N-乙酰葡糖胺酶降解。对四糖组分的结构分析显示如下：（1）N-乙酰葡糖胺之前是一个非硫酸化的糖醛酸残基，其可以是D-葡萄糖醛酸或L-艾杜糖醛酸，但之后是一个葡萄糖醛酸残基。（2）主要组分中的N-乙酰葡糖胺是硫酸化的。（3）很少有糖醛酸残基被硫酸化（4）。结果表明，硫酸乙酰肝素链中含有N-乙酰葡糖胺和N-硫酸化葡糖胺残基的二糖交替区域的硫酸盐含量高于预期，且硫酸基团主要位于己糖胺单元上。
