Microcystin LA, a natural toxin, exerts its cytotoxic exects by inhibiting the serine-threonine protein phosphatases PP1 and PP2A with IC50s of 0.3 and 0.3 nM, respectively.

PTP inhibitor II is an ?inhibitor of cell-permeable protein tyrosine phosphatase (PTP) that covalently binds the catalytic domain of the Src homology region 2 domain-containing phosphatase (SHP-1(ΔSH2))with Ki of128 μM.

[pTyr5] EGFR (988-993) is derived from the autophosphorylation site (Tyr992) of epidermal growth factor receptor (EGFR 988-993). [pTyr5] EGFR (988-993) is often complexed with the catalytically inactive protein-tyrosine phosphate 1B (PTP1B).