Pentasaccharid

A pentasaccharide is a carbohydrate composed of five monosaccharide units linked by glycosidic bonds. It can be a linear chain or a branched structure, and the five units may all be the same (homopentaose) or consist of different sugars (heteropentaose). The specific arrangement of residues and linkages determines its properties and biological interactions.

Pentasaccharides occur as discrete oligosaccharides formed by partial hydrolysis of larger polysaccharides or as defined synthetic products generated by chemical or enzymatic synthesis. They are used in glycobiology as standards and probes to study sugar–protein interactions, enzyme specificities, and glycan building blocks in larger macromolecules such as glycoproteins and glycosaminoglycans. In glycosaminoglycans, sulfation patterns can give rise to biologically active pentasaccharide motifs that influence binding to proteins.

A notable example in biomedicine is the antithrombin-binding pentasaccharide motif within heparin. This specific five-sugar sequence binds antithrombin III with high affinity and is a key determinant of the anticoagulant activity of unfractionated heparin and certain low-molecular-weight heparins. This motif has been a focal point for designing anticoagulant drugs and for understanding how sulfation and saccharide composition control protein recognition.

Analytical and synthetic approaches for pentasaccharides include chemical synthesis, chemoenzymatic methods, and partial degradation of larger polysaccharides, complemented by analytical techniques such as nuclear magnetic resonance spectroscopy, mass spectrometry, and high-performance liquid chromatography.

See also: oligosaccharide, glycosaminoglycan, heparin, glycan microarray.