N-(p-Tosyl)-GPR-pNA is a colorimetric substrate for thrombin.1 Thrombin preferentially binds to and cleaves the Gly-Pro-Arg (GPR) peptide sequence to release p-nitroanilide (pNA), which can be quantified by colorimetric detection at 405 nm as a measure of thrombin activity.
|1. Abildgaard, U., Lie, M., and •deg•rd, O.R. Antithrombin (heparin cofactor) assay with "new" chromogenic substrates (S-2238 and Chromozym TH). Thromb. Res. 11(4), 549-553 (1977).
















