Divalent and Trivalent α-Ketocarboxylic Acids as Inhibitors of Protein Tyrosine Phosphatases

Protein tyrosine phosphatases (PTPases) are important targets for the treatment of insulin resistance in patients with type II diabetes and as antibacterial agents. As a result, there is a growing interest in the development of potent and specific inhibitors for these enzymes. This paper describes a series of inhibitors that contain two or three α-ketocarboxylic acid groups that are designed to form multiple contacts with residues inside or near the active site of phosphatases. The inhibitors have been assayed against three PTPases: the Yersinia PTPase, PTP1B, and LAR. The best of the inhibitors has IC50 values against the Yersinia PTPase and PTP1B of 0.7 and 2.7 μM, respectively. These divalent and trivalent compounds are significantly more potent than their corresponding monovalent analogues. In addition, they show good selectivity for PTP1B and the Yersinia PTPase as compared to LAR.