The Hyaluronic Acid molecule in 3-D

The Hyaluronic Acid molecule - rotatable in 3 dimensions

Hyaluronic Acid (also known as hyaluronan) is a polymer composed of variable numbers of alternating modified glucose units: glucuronic acid and n-acetyl glucosamine.

It is widely distributed in connective tissue and in synovial fluid, and synthesised at the cell surface membrane by polymerisation of disaccharide units. And of course it is often advertised as a component of cosmetics.

Glucuronic acid is based on a glucose molecule with its C6 forming a carboxylic acid group -COOH rather than -CH2OH. This can clearly ionise and gives acidic properties.

N-acetyl glucosamine is derived from a glucose molecule with an amino group attached to C2, and an acetyl group (-CH3CO) projecting from that.

This model - a 'double disaccharide' (?) - contains four such units and it shows the different glycosidic linkages between them. There are alternating β-(1→4) and β-(1→3) glycosidic bonds.

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