The addition of GalNAc to the terminal glucuronate residue forms chondroitin

Chondroitin sulfate N-acetylgalactosaminyltransferases 1 and 2 (CSGALNACT1 and 2) (Uyama et al. 2002, Gotoh et al. 2002) transfer N-acetylgalactosamine (GalNAc) from UDP-GalNAc to the glucuronate (GlcA) residue of the linker sequence. This first addition to the linker determines this GAG to be chondroitin. Chondroitin is comprised of the repeating disaccharide unit GalNAc-GlcA.

硫酸软骨素N-乙酰半乳糖胺基转移酶1和2（CSGALNACT1和2）（Uyama等，2002，Gotoh等，2002）将N-乙酰半乳糖胺（GalNAc）从UDP-GalNAc转移到连接序列中的葡萄糖醛酸（GlcA）残基上。这一首次添加至连接序列的基团决定了该GAG为软骨素。软骨素由重复的二糖单位GalNAc-GlcA构成。