mannosyl

Mannosyl is an adjective used in chemistry and biochemistry to indicate a glycosyl group or residue derived from the sugar mannose. It is applied in systematic naming to describe glycosyl substituents, such as mannosyl groups, glycosides, or mannosylated molecules.

In biology, mannosyl groups are common components of glycoproteins and glycolipids. Mannose residues are added to proteins in the process of glycosylation. In eukaryotes, N-linked glycosylation begins with transfer of a dolichol-linked oligosaccharide that includes several mannose units to an asparagine on a nascent polypeptide; subsequent processing yields high-mannose, hybrid, or complex N-glycans. Mannose-rich glycans play roles in protein folding, stability, cell recognition, and immune interactions.

Nomenclature and examples: The prefix mannosyl- is used to describe structures or substituents containing mannose. Anomeric configuration is often specified as alpha-D-mannopyranosyl or beta-D-mannopyranosyl. The term mannosylation is used to refer to the enzymatic addition of mannose residues (glycosyltransferases) or to the presence of mannose-containing glycosyl groups on a molecule.

Clinical relevance: Abnormalities in mannosylation can lead to congenital disorders of glycosylation, reflecting defects in the biosynthesis or processing of N- or O-linked mannose-containing glycans. Research on mannosylation informs studies of cell signaling, pathogen recognition, and therapeutic glycoprotein design.