Dolichol

Dolichol is an isoprenoid compound synthesized by the same metabolic route as cholesterol (see here). In vertebrate tissues, dolichol contains 18-20 isoprenoid units (90-100 carbons total). Dolichol is phosphorylated by a kinase that uses CTP to form dolichol Phosphate. Dolichol phosphate is the structure upon which the carbohydrate moieties of N-linked glycoproteins are built. After assembly on dolichol phosphate, the carbohydrate structure is transferred to an asparagine residue of a target protein having the sequence Asn-x-Ser/Thr, where X is any amino acid.

See also: Biosynthesis of Glycoconjugates, Figure 16.16, Figure 16.17