Other types of O-glycan biosynthesis - Saccoglossus kowalevskii (acorn worm)

O-linked glycosylation is the attachment of monosaccharides to the hydroxyl groups of amino acids, mostly serine and threonine, and is found in eukaryotes, archaea and bacteria. O-glycans exhibit diverse types of modifications where the innermost monosaccharide is N-acetylgalactosamine (map00512), mannose in mammals (map00515), and others (this map) including N-acetylglucosamine, fucose, glucose, galactose, mannose in yeast and arabinose in plants.