L-Tyrosine Manufacture Standards: AJI92,USP26,EP5 L-TyrosineIndications and UsageTyrosine (abbreviated as Tyr or Y) or 4 ... are transferred by way of protein kinases (so-called receptor tyrosine kinases). Phosphorylation of the hydroxyl group changes the activity of ... the target protein.A tyrosine residue also plays an important role in photosynthesis. In ...