TYR
TYR (tyrosinase) is a copper-containing oxidase that catalyses the initial, rate-limiting step in melanin production from tyrosine. It is also known by the aliases OCAIA, OCA1A and OCA1, reflecting its link to oculocutaneous albinism. Browse Assay Genie's current range of TYR research reagents below, or read on for the biology behind the target.
TYR is a copper-containing oxidase that functions in the formation of pigments such as melanins and other polyphenolic compounds. It catalyses the initial and rate-limiting step in the cascade of reactions that leads from tyrosine to melanin. The enzyme hydroxylates tyrosine to DOPA (3,4-dihydroxyphenylalanine), and it also catalyses the oxidation of DOPA to DOPA-quinone. It may further oxidise DHI (5,6-dihydroxyindole) to indole-5,6 quinone. Because it carries both tyrosine hydroxylase and dopa oxidase activities, and requires copper for function, TYR sits at the head of the melanogenic pathway.
The TYR gene encodes a protein that belongs to the tyrosinase family, which HGNC groups with the oxygenases. Its UniProt subcellular locations are the melanosome and the melanosome membrane, the organelle in which melanin is made. The NCBI Gene summary notes that the enzyme performs the first two steps, and at least one later step, in converting tyrosine to melanin. The human genome also contains a pseudogene that resembles the 3' half of the TYR gene, which is worth bearing in mind when designing nucleic acid assays. Researchers working on tyrosinase often study the mouse ortholog, Tyr.
TYR is best known for its disease relevance. Mutations in the gene result in oculocutaneous albinism, which explains the aliases OCAIA, OCA1A and OCA1. Nonpathologic polymorphisms in the gene contribute to variation in skin pigmentation. This makes the TYR protein a central subject in pigmentation biology, and a common reference point alongside related melanogenic proteins such as TYRP1.
TYR catalyses the initial, rate-limiting step in melanin production from tyrosine, making it a key readout for studies of pigment formation.
Mutations in the TYR gene result in oculocutaneous albinism, and nonpathologic polymorphisms contribute to variation in skin pigmentation.
TYR requires copper and combines tyrosine hydroxylase and dopa oxidase activities, offering a model for oxidase catalysis and DOPA-quinone formation.
TYR localises to the melanosome and its membrane, so it is widely used to examine the organelle where melanin synthesis takes place.
TYR is a copper-containing oxidase that catalyses the initial, rate-limiting step of melanin synthesis. It hydroxylates tyrosine to DOPA, oxidises DOPA to DOPA-quinone, and possibly oxidises DHI to indole-5,6 quinone. It therefore has both tyrosine hydroxylase and dopa oxidase activities.
The HGNC full name is tyrosinase, and the UniProt protein name is Tyrosinase. The aliases and previous symbols OCAIA, OCA1A and OCA1 refer to oculocutaneous albinism, the condition linked to mutations in this gene. The enzyme is classified as EC 1.14.18.1.
The mouse ortholog is Tyr. In humans, TYR mutations result in oculocutaneous albinism, while nonpathologic polymorphisms affect skin pigmentation. Cross-species work should be planned carefully, so check the datasheet of any product for its validated reactivity.
Related melanogenic proteins, tyrosine-metabolising enzymes and similarly named targets with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P14679; product specifications from Assay Genie datasheets.