CD45 protein tyrosine phosphatase: Determination of minimal peptide length for substrate recognition and synthesis of some tyrosine-based electrophiles as potential active-site directed irreversible inhibitors

Using fyn PTK as a template, a series of phosphopeptides 1–11 spanning in length from 1–14 amino acids was prepared. Kinetic evaluation of 1–11 suggest that CD45 does not have a strong preference for its N- or C-terminal amino acids and that extended phosphopeptides are not required for efficient substrate turnover.