Trigger action of dextran sulfate on inactivation of thrombin

Inactivation of thrombin was enhanced by dextran sulfate (DS) coated on polypropylene tubes with plastic adhesive. Long interaction of thrombin with DS was not essential to enhance the enzyme inactivation. Albumin inhibited the inactivation of thrombin by DS-coated tubes, but had no effect after interaction of the enzyme with DS. NaCl, especially, sodium ions, inhibited the inactivation by DS-coated tubes. Enzyme inactivation occurred at 37 degrees C, but not at 4 degrees C. Thus, the inactivation was due not only to ionic interaction with DS, but also to intramolecular perturbation of thrombin.