5-CHROM-81 Thrombin Chromogenic Substrate (Tos-Gly-Pro-Arg-pNA·AcOH), 25 mg Vial is a high-purity synthetic peptide substrate widely used for the quantitative determination of thrombin activity. Upon cleavage by thrombin, it releases p-nitroaniline (pNA), producing a measurable colorimetric signal that enables sensitive and reproducible kinetic assays. Supplied as a 25 mg vial, this chromogenic substrate is ideal for coagulation research, enzyme kinetics, drug development, and diagnostic assay design. Its consistent performance and reliable reactivity make it a trusted tool for both academic and industrial laboratories focused on hemostasis and thrombosis studies.