Sulfotyrosine Recombinant mAb (S-5309)

Sulfotyrosine (sTyr) is the O-sulfated ester of tyrosine. As a common post-translational modification found in higher eukaryotes, it is generated in the Golgi lumen by tyrosylprotein sulfotransferases (TPST-1 and TPST-2), which catalyze the transfer of a sulfate group from the donor PAPS to tyrosine residues. Unlike phosphotyrosine, which primarily participates in intracellular signal transduction, sulfotyrosine modification is irreversible and occurs exclusively on the extracellular domains of secreted or transmembrane proteins. Its core function is to serve as a critical structural element that precisely regulates extracellular protein–protein interactions through its negatively charged sulfate group and aromatic character, playing a "specificity switch" role in numerous physiological and pathological processes—including leukocyte adhesion and migration, hormonal activity, immune responses, and even viral (e.g., HIV) entry.