Heparin as a Polyelectrolyte

Competition for binding to heparin (in essentially salt-free solutions) has been studied for most physiological cations, by ion-exchange,372 equilibrium dialysis,373 c.d.,365 and 23Na-n.m.r. spectroscopy.370 The following order of affinity was generally observed Na+ K+ Mg2+ Ca2+. 

It should be noted that heparin regions that are mainly involved in binding of divalent cations are the regular sequences made up of the 

Also of importance for analytical and structural studies are the complexes with alkylammonium salts, widely used under selective conditions of critical electrolyte concentrations (see Section III). 

---