In the mid-19th century, tyrosine was discovered in casein. Tyrosine comes in two isomers, L-tyrosine and D-tyrosine.L-tyrosine is a natural substance and L-tyrosine is a synthetic substance. And L-tyrosine also plays an important role in the synthesis of melanin.
Melanin is a nitrogenous melanin produced by melanocytes. In the process of melanin synthesis, L-tyrosine is used as the precursor of melanin synthesis. Under the catalysis of tyrosinase, L-tyrosine is hydroxylated into dopa, which is then transformed into dodo quinone. After polymerization to achieve the effect of synthesis of melanin.