Capillary zone electrophoresis for the study of the binding of antithrombin to low-affinity heparin

When low-affinity interactions between glycosaminoglycans and precious proteins are studied, it is imperative to design an experimental set-up that consumes as little material as possible. To evaluate the applicability of the CZE technique to this problem, we explored the interaction between antithrombin and low-affinity heparin. In a series of CZE experiments we demonstrated that the mobility of antithrombin increases gradually as increased concentrations of low-affinity heparin were added to the electrolyte. The results were, as expected, consistent with the general algorithm for monovalent binding. The binding constant was estimated at 20+/-6 mu M in excellent agreement with the value reported in the literature.