Stimulation by dextran sulfate of denaturation of bovine thrombin.

At high thrombin concentration, loss of enzyme activity was proportional to the initial enzyme concentration. At low thrombin concentration, loss of activity followed first order kinetics, indicating mainly denaturation (inactivation) of the enzyme. Dextran sulfate stimulated thrombin denaturation, while serum albumin and polyethylene glycol 6000 (PEG) protected the enzyme from denaturation. These results indicate that the enzyme molecule is stabilized by weak interactions with albumin and PEG, but destabilized by strong interaction with dextran sulfate.