Selective Protein Tyrosine Phosphatase 1B Inhibitors:  Targeting the Second Phosphotyrosine Binding Site with Non-Carboxylic Acid-Containing Ligands

Protein tyrosine phosphatase (PTPase) 1B (PTP1B) has been implicated as a key negative regulator of both insulin and leptin signaling cascades. We identified several salicylic acid-based ligands for the second phosphotyrosine binding site of PTP1B using a NMR-based screening. Structure-based linking with a catalytic site-directed oxalylarylaminobenzoic acid-based pharmacophore led to the identification of a novel series of potent PTP1B inhibitors exhibiting 6-fold selectivity over the highly homologous T-cell PTPase (TCPTP) and high selectivity over other phosphatases.