cofactor, chromogenic, AT-III, antithrombin-heparin, inhibit, Inhibitor, H-D-Phe-Pip-Arg-pNA, HDPhePipArgpNA dihydrochloride, H-D-Phe-Pip-Arg-pNA Dihydrochloride, H-D-Phe-Pip-Arg-pNA dihydrochloride, fibrinogen, H D Phe Pip Arg pNA dihydrochloride, S2238 Dihydrochloride, S-2238 dihydrochloride, S-2238 Dihydrochloride, S2238, S-2238, S 2238 Dihydrochloride, S 2238, substrate, thrombin
H-D-Phe-Pip-Arg-pNA dihydrochloride (S-2238) is a thrombin-specific chromogenic substrate that mimics fibrinogen. It enables sensitive and accurate quantification of antithrombin (AT-III) activity in vitro, making it essential for coagulation research and heparin therapy monitoring.