Protein phosphorylation is one of the most important post-translational modification processes. Phosphorylation is reversibly regulated by Protein Kinases (PKs) and Protein Phosphatases (PTPs). PTP1B (PTPN1) is known to catalyze dephosphorylation of insulin receptor kinases and plays a critical role in insulin signaling. The Fluorogenic PTP1B (Catalytic Domain) Assay Kit is designed to inhibitors of the catalytic region of PTP1B in a homogeneous assay with no time-consuming washing steps. Note: To identify inhibitors of the regulatory region of PTP1B, please use our Fluorogenic PTP1B (Full Length) Assay Kit, #79766).