Proteoglycan

Not to be confused with bacterial peptidoglycan. Proteoglycans are proteins that are heavily glycosylated. The basic proteoglycan unit consists of a “core protein” with one or more covalently attached glycosaminoglycan (GAG) chain(s). The point of attachment is a Ser residue to which the glycosaminoglycan is joined through a tetrasaccharide bridge.