Biotinylated hyaluronic acid: a new tool for probing hyaluronate-receptor interactions.

Hyaluronic acid (HA) is a linear polysaccharide composed of repeating disaccharide units of D-glucuronic acid (GlcUA) and N-acetyl-D-glucosamine (GlcNAc). Hyaluronate plays an important role in many biological processes as mediated by its interactions with a number of HA-binding proteins (the "hyaladherins") and with the cell surface HA-receptor, CD44. Studies of hyaluronate-hyaladherin interactions would be greatly facilitated by the availability of molecular probes derived from HA. We recently reported a convenient chemical modification of hyaluronate that introduces multiple pendant amine functionalities onto the HA carboxylate residues. We now report the preparation of biotinylated hyaluronic acid (molecular weight = 1.2 x 10(6) Da) as a probe for histochemical and immunochemical characterization of HA-binding proteins. Approximately one-third of the available HA glucuronate residues could be readily biotinylated in high molecular weight HA.