Tyrosine is a non-necessary phenylalanine-derived amino acid. Tyrosine’s framework is built a para-hydroxylated phenyl ring linked to a pentanoic acid team, and that is a five member carbon chain with a carboxyl (C(=O)OH) group within the terminal carbon. This pentanoic acid chain is substituted at R2 with an amino team https://revivalschem.com/product/buy-escaline-fumarate/