Oxidized PTP Active Site Products

Oxidation of the essential cysteine in the active site of protein tyrosine phosphatases (PTPs) is believed to play an important role in regulating the activity of these enzymes. Rapid, oxidant-dependent inhibition of phosphatases such as PTP1B, TC-PTP and SHP-2 may play a role in fine tuning the responsiveness of receptor tyrosine kinases for growth factors. The initial oxidation to a sulfenic acid (-SOH) is reversible, but oxidation can progress to an irreversible sulfonic acid (-SO3H) that can be detected by antibodies made against an oxidized peptide containing the PTP active site consensus sequence.