from the estimated concentration of heparan sulphate on the endothelial cell surface it is proposed that the non-thrombogenic property of blood vessels is due to the acceleration of the factor xa or prothrombinase : atiii interaction by the greater mass of surface-bound heparan sulphate rather than by the much smaller proportion of heparin-like molecules ( with high affinity for antithrombin iii ) which may be present .
C0015520
factor xa
C0015518
prothrombinase