||Tyrosinase definition in biology refers to a copper-containing enzyme present in plant and animal that catalyzes the oxidation of tyrosine into melanin and other pigments. More specifically, it catalyzes four steps in the melanin and catecholamine synthesis pathways. Tyrosinase deficiency is thought to be responsible for albnisim. Like tyrosine hydroxylase (EC 22.214.171.124), it can catalyze the formation of L-DOPA in the brain and nervous system. It oxidizes monophenols, but like catecholoxidase (EC 126.96.36.199), it can also oxidize o-diphenols to o-quinones. Like what we see the tyrosinase enzyme in potato, the blackening of a peeled or sliced potato is due to its exposure to air. Enzyme tyrosinase can be found in many foods, such as in cheese, chocolate, orange, tuna, animal liver etc. It is involved in cancer, Parkinson’s, pigmentation diseases, Alzheimer’s and obesity. Much of the research and inhibitor screening has used mushroom tyrosinase. And many experiments regarding tyrosinase enzyme kinetics had been done to determine if it is stereospecific. However, mushroom tyrosinase interacts very differently with substrates and inhibitors compared to the human enzyme. In addition, commercially available mushroom tyrosinase is not always of good purity. Recombinant versions of human tyrosinase amino acids 1-345 or 1-378, also available commercially, are not functional due the lack of critical catalytic and structural residues.