Design and synthesis of an activity probe for protein tyrosine phosphatases

Protein tyrosine phosphatases (PTPases:) are an important class of enzymes involved in the regulation of many cellular events. Here we describe the de sign and synthesis of an activity probe 2 targeting these PTPases. This mec hanism-based activity probe adopts a cassette-like design; a phosphate grou p serves as the recognition head and a fluorescent diethylaminocoumarin der ivative acts as the reporter group. Compound 3 was phosphorylated with dial lyl phosphorochloridate and then fluorinated with DAST to give versatile in termediate 5. The Boc protective group of compound 5 was removed by TFA to make available the amino group where a diethylaminocoumarin chromophore was later attached. Final deprotection of the allyl group from the phosphate h ead gives our complete activity probe 2. It will be used in the labeling st udy of PTPases from various sources.