∆UA – (GalNAc,6S or 4S – GlcA)n – GalNAc,6S or 4S
where n is number of disaccharide units
n = 1 in a tetrasaccharide (dp4)
n = 2 in a hexasaccharide (dp6)
n = 3 in an octasaccharide (dp8) etc…..
The uronic acid (∆UA) at the non-reducing ends of the oligosaccharides has a C4-C5 double bond as a result of endolytic scission.
The main disaccharide repeat in the original chondroitin sulphate is GlcA – GalNAc sulphated at C-6 or C-4 of the GalNAc residue; the CSD disaccharide unit (GlcA,2S – GalNAc,6S) is a minor component comprising approx. 5% of total disaccharides.
Main Chondroitin Sulphate AC Disaccharide Unit