monophenol monooxygenase
EC number
CAS number 9002-10-2
IntEnz IntEnz view
ExPASy NiceZyme view
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / EGO
Tyrosinase (oculocutaneous albinism IA)
External IDs OMIM606933 MGI98880 HomoloGene30969 GeneCards: TYR Gene
EC number
RNA expression pattern
PBB GE TYR 206630 at tn.png
More reference expression data
Species Human Mouse
Entrez 7299 22173
Ensembl ENSG00000077498 ENSMUSG00000004651
UniProt P14679 Q3UFK9
RefSeq (mRNA) NM_000372.4 NM_011661.4
RefSeq (protein) NP_000363.1 NP_035791.1
Location (UCSC) Chr 11:
88.91 – 89.03 Mb
Chr 7:
94.57 – 94.64 Mb
PubMed search [1] [2]

Tyrosinase also known as monophenol monooxygenase is an enzyme that catalyses the oxidation of phenols (such as tyrosine) and is widespread in plants and animals. Tyrosinase is a copper-containing enzyme present in plant and animal tissues that catalyzes the production of melanin and other pigments from tyrosine by oxidation, as in the blackening of a peeled or sliced potato exposed to air. It is found inside melanosomes. In humans, the tyrosinase enzyme is encoded by the TYR gene.[1]


Clinical significance

A mutation in the tyrosinase gene resulting in impaired tyrosinase production leads to type I oculocutaneous albinism, a hereditary disorder that affects one in every 17,000 people.[2]

Catalyzed reaction

Tyrosinase carries out the oxidation of phenols such as tyrosine and dopamine using dioxygen (O2). In the presence of catechol, benzoquinone is formed (see reaction below). Hydrogens removed from catechol combine with oxygen to form water.


The substrate specificity becomes dramatically restricted in mammalian tyrosinase which utilizes only L-form of tyrosine or DOPA as substrates, and has restricted requirement for L-DOPA as cofactor.[3]

Tyrosinase structure

Tyrosinases have been isolated and studied from a wide variety of plant, animal and fungal species. Tyrosinases from different species are diverse in terms of their structural properties, tissue distribution and cellular location.[4] It has been suggested that there is no common tyrosinase protein structure occurring across all species.[5] The enzymes found in plant, animal and fungal tissue frequently differ with respect to their primary structure, size, glycosylation pattern and activation characteristics. However, all tyrosinases have in common a binuclear type 3 copper centre within their active site. Here two copper atoms are each coordinated with three histidine residues.

Common central domain of tyrosinase
Symbol Tyrosinase
Pfam PF00264
InterPro IPR002227
SCOP 1hc2

Transmembrane protein and sorting

Human tyrosinase is a single membrane spanning transmembrane protein.[6] In humans, tyrosinase is sorted into melanosomes[7] and the catalytically active domain of the protein resides within melanosomes. Only a small enzymatically non-essential part of the protein extends into the cytoplasm of the melanocyte.

Active site

The two copper atoms within the active site of tyrosinase enzymes interact with dioxygen to form a highly reactive chemical intermediate that then oxidizes the substrate. The activity of tyrosinase is similar to catechol oxidase, a related class of copper oxidase. Tyrosinases and catechol oxidases are collectively termed polyphenol oxidases.

Crystallographic structure of a Streptomyces derived tyrosinase in complex with a so called "caddie protein".[8] In all models only the tyrosinase molecule is shown, copper atoms are shown in green and the molecular surface is shown in red. In models D and E histidine amino acids are shown as a blue line representation. From model E it can be clearly seen that each copper atom within the active site is indeed complexed with three histidine residues, forming a type 3 copper center. It can also be seen from models C and D that the active site for this protein sits within a pillus formed on the molecular surface of the molecule.

Gene regulation

The gene for tyrosinase is regulated by the Microphthalmia-associated transcription factor.[9][10]


  1. ^ Barton DE, Kwon BS, Francke U (July 1988). "Human tyrosinase gene, mapped to chromosome 11 (q14----q21), defines second region of homology with mouse chromosome 7". Genomics 3 (1): 17–24. doi:10.1016/0888-7543(88)90153-X. PMID 3146546. 
  2. ^ Witkop CJ (October 1979). "Albinism: hematologic-storage disease, susceptibility to skin cancer, and optic neuronal defects shared in all types of oculocutaneous and ocular albinism". Ala J Med Sci 16 (4): 327–30. PMID 546241. 
  3. ^ Hearing VJ, Ekel TM, Montague PM, Nicholson JM (February 1980). "Mammalin tyrosinase. Stoichiometry and measurement of reaction products". Biochim. Biophys. Acta 611 (2): 251–68. PMID 6766744. 
  4. ^ Mayer, AM (2006). "Polyphenol oxidases in plants and fungi: Going places? A review". Phytochemistry 67 (21): 2318–2331. doi:10.1016/j.phytochem.2006.08.006. PMID 16973188. 
  5. ^ Jaenicke, E and Decker, H. (2003). "Tyrosinases from crustaceans form hexamers". Biochem. J. 371 (Pt 2): 515–523. doi:10.1042/BJ20021058. PMC 1223273. PMID 12466021. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1223273. 
  6. ^ Kwon BS, Haq AK, Pomerantz SH, Halaban R (November 1987). "Isolation and sequence of a cDNA clone for human tyrosinase that maps at the mouse c-albino locus". Proc. Natl. Acad. Sci. U.S.A. 84 (21): 7473–7. doi:10.1073/pnas.84.21.7473. PMC 299318. PMID 2823263. http://www.pnas.org/cgi/pmidlookup?view=long&pmid=2823263. 
  7. ^ Theos AC, Tenza D, Martina JA, Hurbain I, Peden AA, Sviderskaya EV, Stewart A, Robinson MS, Bennett DC, Cutler DF, Bonifacino JS, Marks MS, Raposo G (November 2005). "Functions of adaptor protein (AP)-3 and AP-1 in tyrosinase sorting from endosomes to melanosomes". Mol. Biol. Cell 16 (11): 5356–72. doi:10.1091/mbc.E05-07-0626. PMC 1266432. PMID 16162817. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1266432. 
  8. ^ PDB 1WX3; Matoba Y, Kumagi, T. et al. (2006). "Crystallographic evidence that the dinuclear copper center of tyrosinase is flexible during catalysis". J. Biol. Chem. 281 (13): 8981–8990. doi:10.1074/jbc.M509785200. PMID 16436386. 
  9. ^ Hou L, Panthier JJ, Arnheiter H (2000). "Signaling and transcriptional regulation in the neural crest-derived melanocyte lineage: interactions between KIT and MITF". Development 127 (24): 5379–89. PMID 11076759. 
  10. ^ Hoek KS, Schlegel NC, Eichhoff OM, Widmer DS, Praetorius C, Einarsson SO, Valgeirsdottir S, Bergsteinsdottir K, Schepsky A, Dummer R, Steingrimsson E (2008). "Novel MITF targets identified using a two-step DNA microarray strategy". Pigment Cell Melanoma Res. 21 (6): 665–76. doi:10.1111/j.1755-148X.2008.00505.x. PMID 19067971. 

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Look at other dictionaries:

  • Tyrosinase — Masse/Länge Primärstruktur 511 Aminosäuren …   Deutsch Wikipedia

  • tyrosinase — [ tirozinaz ] n. f. • 1897; de tyrosine et ase ♦ Biochim. Enzyme qui active l oxydation de la tyrosine, aboutissant à la production de mélanine. ● tyrosinase nom féminin Enzyme qui oxyde la tyrosine en mélanine. (L albinisme est dû à un déficit… …   Encyclopédie Universelle

  • tyrosinase — tyrosinase. См. тирозиназа. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • tyrosinase — [tī′rō sin ās΄, tir′ōsin ās΄; tī rä′sin ās΄] n. [< TYROSINE + ASE] an enzyme, found in plants and animals, that catalyzes the oxidation of the amino acid tyrosine and is involved in the formation of the dark pigment melanin …   English World dictionary

  • Tyrosinase — La tyrosinase (ou catéchol oxydase) est une enzyme qui catalyse l oxydation des phénols (comme la tyrosine) et elle est très répandue parmi les plantes, les animaux et les mycètes. Une personne ayant un gène de tyrosinase mutée est atteinte d… …   Wikipédia en Français

  • tyrosinase — A copper containing protein (a monoxygenase) that catalyses the oxidation of tyrosine, and sets in train spontaneous reactions that yield melanin, the black pigment of skin, hair and eyes. The first intermediate is 3,4 dihydroxyphenylalanine… …   Dictionary of molecular biology

  • Tyrosinase related protein — (TRP) ist der veraltete Name für zwei Enzyme: TRP 2: L Dopachrom Tautomerase TRP 1: 5,6 Dihydroxyindol 2 carbonsäure Oxidase Diese Seite ist eine Begriffsklärung zur Unterscheidung mehrerer mi …   Deutsch Wikipedia

  • tyrosinase peptide — A protein that is made from tumor cells and is used in a vaccine against melanoma. A tyrosinase peptide vaccine may stimulate the body s immune system to find and kill melanoma cells …   English dictionary of cancer terms

  • tyrosinase — noun Date: 1896 a copper containing enzyme that promotes the oxidation of phenols (as tyrosine) and is widespread in plants and animals …   New Collegiate Dictionary

  • tyrosinase — /tuy roh si nays , nayz , tir oh /, n. Biochem. an oxidizing enzyme, occurring in plant and animal tissues, that catalyzes the aerobic oxidation of tyrosine into melanin and other pigments. [1895 1900; TYROSINE + ASE] * * * …   Universalium

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