Zinc ions promote the interaction between heparin and heparin cofactor II

The effects of bivalent cations on heparin binding, structure, and thrombin inhibition rates of heparin cofactor II were examined. Zn2+ - and to a lesser extent Cu2+ and Ni2+ - enhanced the interaction between heparin cofactor II and heparin as demonstrated by heparin affinity chromatography and surface plasmon resonance experiments. Metal chelate chromatography and increased intrinsic protein fluorescence in the presence of Zn2+ indicated that heparin cofactor II as metal ion-binding properties. The results are compatible with the hypothesis that Zn2+ induces a conformational change in heparin cofactor IIhat favors its interaction with heparin. (C) 2003 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.