Interaction of heparin with annexin V

The energetics and kinetics of the interaction of heparin with the Ca+2 and phospholipid binding protein annexin V, was examined and the minimum oligosaccharide sequence within heparin that binds annexin V was identified, Affinity chromatography studies confirmed the Ca+2 dependence of this binding interaction. Analysis of the data obtained from surface plasmon resonance afforded a K-d of similar to 21 nM for the interaction of annexin V with end-chain immobilized heparin and a K-d of similar to 49 nM for the interaction with end-chain immobilized heparan sulfate. Isothermal titration calorimetry showed the minimum annexin V binding oligosaccharide sequence within heparin corresponds to an octasaccharide sequence. The K-d Of a heparin octasaccharide binding to annexin V was similar to 1 mu M with a binding stoichiometry of 1:1, (C) 1999 Federation of European Biochemical Societies.