Heparin-polypeptide interaction. Near-i.r. spectroscopy in an anhydrous dispersant allows the involvement of polymer-associated water to be assessed.

Involvement of polymer-associated water in the interaction of heparin with poly-L-arginine and poly-L-lysine was studied by i.r. spectroscopy of complexes suspended in a non-aqueous dispersant. Movement of i.r. absorption bands due to heparin-associated water to lower frequencies upon polymer interaction indicates that hydrogen-bonding accompanies complexation. We suggest that this bonding includes water bridging between the interacting species, and that the resulting changes in water chemistry may affect the biological activity of such interacting macromolecules.