L-Phosphotyrosine can be used in the detection and quantification of tyrosine phosphorylation in proteins and as starting material in the synthesis of fluorescent substrates for protein tyrosine phosphatase assays. Furthermore, it has been incorporated in cyclic hexapeptides for studying intramolecular quenching of tryptophan fluorescence.
L-Phosphotyrosine inhibits cellular growth by activating protein tyrosine phosphatases (Mishra and Hamburger). The phosphorylated amino acid protects TP53 wild-type cells against ionizing radiation.