Redox regulation of protein tyrosine phosphatase 1B (PTP1B): Importance of steric and electronic effects on the unusual cyclization of the sulfenic acid intermediate to a sulfenyl amide

The redox regulation of protein tyrosine phosphatase 1B (PTP1B) via the unusual transformation of its sulfenic acid (PTP1B-SOH) to a cyclic sulfenyl amide intermediate is studied by using small molecule chemical models. These studies show that the substituents that can induce steric environment and alter the electronic properties around the sulfenic acid moiety by S⋯N or S⋯O nonbonded interactions can influence the cyclization process. The amino acid residues in the close proximity of the sulfenic acid moiety in PTP1B may play important roles via such interactions in the cyclization of PTP1B-SOH to produce the corresponding sulfenyl amide.