Tyrosine is often a non-important phenylalanine-derived amino acid. Tyrosine’s framework is made a para-hydroxylated phenyl ring connected to a pentanoic acid group, that's a 5 member carbon chain with a carboxyl (C(=O)OH) group to the terminal carbon. This pentanoic acid chain is substituted at R2 using an amino group in https://revivalschem.com/product/buy-purple-mandala-mix/