H-D-Phe-Pip-Arg-pNA hydrochloride, a chromogenic substrate, mimics the N-terminal segment of the A alpha chain of fibrinogen, the native substrate of thrombin. It displays specificity towards thrombin and is employed for quantifying antithrombin-heparin cofactor (AT-III). The utilization of H-D-Phe-Pip-Arg-pNA hydrochloride in the AT-III assay enables a sensitive, accurate, and straightforward measurement process.

H-D-Phe-Pip-Arg-pNA (S-2238) acetate is a chromogenic substrate designed based on the N-terminal fragment of the A alpha chain of fibrinogen, which is the physiological target of thrombin. As a specific indicator of thrombin activity, H-D-Phe-Pip-Arg-pNA acetate is utilized to quantify. This assay, utilizing H-D-Phe-Pip-Arg-pNA acetate, ensures high sensitivity, accuracy, and ease of execution.