1.14.18.1: tyrosinase
This is an abbreviated version!
For detailed information about tyrosinase, go to the full flat file.
Word Map on EC 1.14.18.1
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1.14.18.1
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melanin
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melanoma
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melanocyte
-
melanogenesis
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melanosomes
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cosmetic
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microphthalmia-associated
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hyperpigmentation
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melanogenic
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catechols
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polyphenols
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kojic
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copper
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albinism
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whitening
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hair
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keratinocytes
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albino
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flavonoid
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biosensors
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o-quinone
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amperometric
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phytochemical
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pigmentary
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vitiligo
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tautomerase
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laccase
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abts
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alpha-msh
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melanization
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depigmentation
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hydroquinone
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electrode
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melanocortins
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2,2-diphenyl-1-picrylhydrazyl
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copper-binding
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polyphenoloxidase
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frap
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biotechnology
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agriculture
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pharmacology
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hla-a2
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nutrition
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1,1-diphenyl-2-picrylhydrazyl
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food industry
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hemocyanins
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environmental protection
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l-3,4-dihydroxyphenylalanine
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crest-derived
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drug development
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microphthalmia
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medicine
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agaricus
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butyrylcholinesterase
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melanoma-associated
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copper-containing
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decolor
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bisporus
- 1.14.18.1
- melanin
- melanoma
- melanocyte
-
melanogenesis
- melanosomes
-
cosmetic
-
microphthalmia-associated
- hyperpigmentation
-
melanogenic
- catechols
- polyphenols
-
kojic
- copper
- albinism
-
whitening
- hair
-
keratinocytes
-
albino
- flavonoid
-
biosensors
- o-quinone
-
amperometric
-
phytochemical
-
pigmentary
- vitiligo
-
tautomerase
- laccase
- abts
- alpha-msh
-
melanization
-
depigmentation
- hydroquinone
-
electrode
-
melanocortins
-
2,2-diphenyl-1-picrylhydrazyl
-
copper-binding
- polyphenoloxidase
-
frap
- biotechnology
- agriculture
- pharmacology
-
hla-a2
- nutrition
-
1,1-diphenyl-2-picrylhydrazyl
- food industry
- hemocyanins
- environmental protection
- l-3,4-dihydroxyphenylalanine
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crest-derived
- drug development
- microphthalmia
- medicine
- agaricus
- butyrylcholinesterase
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melanoma-associated
-
copper-containing
-
decolor
- bisporus
Reaction
2 L-dopa
+
Synonyms
AbPPO1, AbPPO4, AbTYR, aurone synthase, catalase-phenol oxidase, catechol oxidase, catecholase, CATPO, chlorogenic acid oxidase, chlorogenic oxidase, cresolase, cresolase/monophenolase, CsPPO, CZA14Tyr, deoxy-tyrosinase, dihydroxy-L-phenylalanine:oxygen oxidoreductase, Diphenol oxidase, diphenolase, dopa oxidase, EC 1.10.3.1, EC 1.14.17.2, Hc-derived phenoloxidase, Hc-phenoloxidase, HcPO, HdPO, hemocyanin-derived phenoloxidase, jrPPO1, jrTYR, L-DOPA monophenolase, L-DOPA oxidase, L-DOPA:oxygen oxidoreductase, L-tyrosine hydroxylase, MdPPO1, melC2, MelC2 tyrosinase, met-tyrosinase, monophenol dihydroxyphenylalanine:oxygen oxidoreductase, monophenol monooxidase, monophenol monooxygenase, monophenol monoxygenase, monophenol oxidase, monophenol oxygen oxidoreductase, monophenol, 3,4-dihydroxy L-phenylalanine (L-DOPA):oxygen oxidoreductase, monophenol, dihydroxy-L-phenylalanine oxygen oxidoreductase, monophenol, dihydroxy-L-phenylalanine:oxygen oxidoreductase, monophenol, dihydroxyphenylalanine:oxygen oxidoreductase, monophenol, L-Dopa: oxidoreductase, monophenol, L-DOPA: oxygen oxidoreductase, monophenol, o-diphenol: oxygen oxidoreductase, monophenol, o-diphenol:O2 oxidoreductase, monophenol, o-diphenol:oxygen oxido-reductase, monophenol, o-diphenol:oxygen oxidoreductase, monophenol, polyphenol oxidase, monophenol: dioxygen oxidoreductases, hydroxylating, monophenolase, monphenol mono-oxygenase, More, mTyr, murine tyrosinase, mushroom tyrosinase, mushroom tyrosine, N-acetyl-6-hydroxytryptophan oxidase, o-diphenol oxidase, o-diphenol oxidoreductase, o-diphenol oxygen oxidoreductase, o-diphenol: O2 oxidoreductase, o-diphenol: oxidoreductase, o-diphenol:O2 oxidoreductase, o-diphenol:oxygen oxidoreductase, o-diphenolase, OCA1, Orf13, oxygen oxidoreductase, phenol oxidase, phenol oxidases, phenolase, phenoloxidase, PO, polyaromatic oxidase, polyphenol oxidase, polyphenol oxidase 3, polyphenol oxidase 4, polyphenol oxidase B, polyphenolase, polyphenoloxidase, PotPPO, PPO, PPO 3, PPO B, PPO1, PPO2, PPO3, pro-PO III, prophenoloxidase III, pyrocatechol oxidase, SPRTyr, ST94, ST94t, tryosinase, tryrosinase, TY, tyr, TYR1, TYR2, tyrA, TyrBm, tyrosinase, tyrosinase 2, tyrosinase 4, tyrosinase diphenolase, tyrosine-dopa oxidase
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1.14.18.1 tyrosinaseAdvanced search results
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results (Natural Substrates Products
Natural Substrates Products on EC 1.14.18.1 - tyrosinase
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NATURAL SUBSTRATE 
NATURAL PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
2 2',3,4,4',6'-pentahydroxychalcone + O2
bracteatin + 2 H2O
-
-
-
?
2',4',6',4-tetrahydroxychalcone + O2
aureusidin + H2O
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-
-
?
chlorogenic acid + O2
?
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formation of a highly reactive o-quinone intermediate which then can interact with NH2 groups of lysine, SCH3 groups of methionines and indole rings of tryptophan in nucleophilic addition and in polymerization reactions, the so-called browning and greening reactions
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-
?
2 4-methylcatechol + O2
2 4-methyl-1,2-benzoquinone + 2 H2O
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-
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?
2 L-dopa + O2
2 dopaquinone + 2 H2O
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-
744014, 744483, 744486, 744488, 744490, 744491, 744495, 744511, 744669, 744671, 744676, 744818, 744819, 745086, 745095, 745130, 745133, 745138, 745139, 745406, 745819, 746193, 746346, 746498
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-
?
2 L-dopa + O2
2 dopaquinone + 2 H2O
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-
-
?
L-DOPA + O2
dopaquinone + H2O
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1% activity compared to 3,4-dihydroxyhydrocinnamic acid
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-
?
L-tyrosine + L-dopa + O2
L-dopa + dopaquinone + H2O
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pathway of melanin biosynthesis, detailed overview
cytotoxicity of L-DOPA
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?
L-tyrosine + L-dopa + O2
L-dopa + dopaquinone + H2O
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air saturated 50 mM phosphate buffer, pH 7.0, 30°C
polymerizes to form melanin-like pigments
-
?
L-tyrosine + O2
dopaquinone + H2O
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-
-
-
?
L-tyrosine + O2
dopaquinone + H2O
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6% activity compared to 3,4-dihydroxyhydrocinnamic acid
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-
?
L-tyrosine + O2 + AH2
L-3,4-dihydroxyphenylalanine + H2O + A
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enzyme initiates the formation of pigmentation, absence leads to forms of albinism
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-
?
L-tyrosine + O2 + AH2
L-3,4-dihydroxyphenylalanine + H2O + A
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rate-limiting enzyme in melanin biosynthesis
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-
?
tyrosine + O2
dopaquinone + H2O
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744483, 744486, 744488, 744495, 744511, 744676, 744819, 745130, 745138, 745139, 746193, 746346, 746498
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?
additional information
?
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role of the enzyme in the biosynthetic scheme of betalains, overview
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-
?
additional information
?
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catalyzing the rate-limiting step for melanin biosynthesis
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?
additional information
?
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tyrosinase possesses cresolase/monophenolase and/or catecholase/diphenolase activities
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?
additional information
?
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mushroom tyrosinase-associated lectin-like protein (MtaL) binds to mature Agaricus bisporus tyrosinase in vivo, binding structure analysis, overview. MtaL undergoes conformational changes upo tyrosinase binding, but the general beta-trefoil fold is conserved, it is essential for carbohydrate interaction in other lectin-like proteins
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?
additional information
?
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mushroom tyrosinase-associated lectin-like protein (MtaL) binds to mature Agaricus bisporus tyrosinase in vivo, binding structure analysis, overview. MtaL undergoes conformational changes upo tyrosinase binding, but the general beta-trefoil fold is conserved, it is essential for carbohydrate interaction in other lectin-like proteins
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?
additional information
?
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the enzyme catalyzes the oxidation of both monophenols (cresolase or monophenolase activity) and o-diphenols (catecholase or diphenolase activity) into reactive o-quinones
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?
additional information
?
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tyrosinase exhibits two mechanisms of oxidation: monooxygenase (EC 1.14.18.1) and oxidase (1.10.3.1) activities. The enzyme is characterised by possessing four discrete oxidation states (deoxy-, oxy-, met- and deact-tyrosinase), detailed overview. The enzyme exhibits a lag period when employed in vitro and it is slowly inactivated by catechol substrates and is rapidly inactivated by resorcinols
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-
?
additional information
?
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substrate specificity allows elucidation of a likely mechanism of aurone formation from 2,4,6,4-tetrahydroxychalcone or PHC involving both tyrosinase and catechol oxidase activities of the Antirrhinum majus PPO, pathway overview. Starting with THC, tyrosinase and catechol oxidase activity result in 3-hydroxylation and formation of the corresponding o-quinone. Whether aureusidine synthase PPO carries out the 3-hydroxylation reaction in vivo, or whether a cytochrome P450 chalcone 3-hydroxylase is also involved is not definitively established. Aureusidine synthase, EC 1.21.3.6, likely forms the same quinone from 2',3,4,4',6'-pentahydroxychalcone without the need for the 3-hydroxylation step. The resulting quinone is predicted to undergo a 2-step non-enzyme mediated rearrangement to form aureusidin
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?
additional information
?
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tyrosinase is a bifunctional enzyme that catalyzes the o-monohydroxylation of monophenols (phenols) to their corresponding o-diphenols (o-cresolase or monophenolase, EC 1.14.18.1) and their subsequent oxidation (catechol oxidase or diphenolase, EC 1.103.1) into reactive o-quinones. Molecular oxygen is used as an electron acceptor, and it is reduced to water in both the reactions. Subsequently, the resulting o-quinones undergo non-enzymatic oxido-reduction reactions with various nucleophilic moieties, producing intermediates which auto-polymerize spontaneously in dark brown pigments. The monophenolase activity is the initial rate-determining reaction in the process
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?
additional information
?
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tyrosinase is a bifunctional enzyme that catalyzes the o-monohydroxylation of monophenols (phenols) to their corresponding o-diphenols (o-cresolase or monophenolase, EC 1.14.18.1) and their subsequent oxidation (catechol oxidase or diphenolase, EC 1.103.1) into reactive o-quinones. Molecular oxygen is used as an electron acceptor, and it is reduced to water in both the reactions. Subsequently, the resulting o-quinones undergo non-enzymatic oxido-reduction reactions with various nucleophilic moieties, producing intermediates which auto-polymerize spontaneously in dark brown pigments. The monophenolase activity is the initial rate-determining reaction in the process
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?
additional information
?
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tyrosinase is a bifunctional enzyme that catalyzes the o-monohydroxylation of monophenols (phenols) to their corresponding o-diphenols (o-cresolase or monophenolase, EC 1.14.18.1) and their subsequent oxidation (catechol oxidase or diphenolase, EC 1.103.1) into reactive o-quinones. Molecular oxygen is used as an electron acceptor, and it is reduced to water in both the reactions. Subsequently, the resulting o-quinones undergo non-enzymatic oxido-reduction reactions with various nucleophilic moieties, producing intermediates which auto-polymerize spontaneously in dark brown pigments. The monophenolase activity is the initial rate-determining reaction in the process
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?
additional information
?
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most plant polphenol oxidases have catechol oxidase activity (oxidation of o-diphenols to their corresponding o-quinones, EC1.10.3.1) and the ability to hydroxylate monophenols to o-diphenols (tyrosinase, EC 1.14.18.1)
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?
additional information
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polyphenol oxidases (PPOs) are nuclear-encoded copper-containing metalloproteins involved in either the hydroxylation of monophenols to o-diphenols (EC 1.14.18.1, monophenol monoxinase, tyrosinase, and cresolase) or dehydrogenation of o-diphenols to o-quinones (EC1.10.3.1, diphenol oxygen oxidoreductase and catecholase). The enzyme from Camellia sinensis oxidizes epicatechins to yield theaflavins and thearubigins
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?
additional information
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synthesis of theaflavins of polyphenol oxidase isozymes from tea leaves
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additional information
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synthesis of theaflavins of polyphenol oxidase isozymes from tea leaves
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?
additional information
?
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mechanical damage by Hemileia vastatrix fungus, the causal agent of the leaf orange rust disease, inoculation and Leucoptera coffeella, the coffee leaf miner, infestation caused different responses in PPO activity in different Coffea species, level of damage or resistance, overview
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?
additional information
?
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Coffea guarini
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mechanical damage by Hemileia vastatrix fungus, the causal agent of the leaf orange rust disease, inoculation and Leucoptera coffeella, the coffee leaf miner, infestation caused different responses in PPO activity in different Coffea species, level of damage or resistance, overview
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?
additional information
?
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mechanical damage by Hemileia vastatrix fungus, the causal agent of the leaf orange rust disease, inoculation and Leucoptera coffeella, the coffee leaf miner, infestation caused different responses in PPO activity in different Coffea species, level of damage or resistance, overview
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?
additional information
?
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mechanical damage by Hemileia vastatrix fungus, the causal agent of the leaf orange rust disease, inoculation and Leucoptera coffeella, the coffee leaf miner, infestation caused different responses in PPO activity in different Coffea species, level of damage or resistance, overview
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?
additional information
?
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mechanical damage by Hemileia vastatrix fungus, the causal agent of the leaf orange rust disease, inoculation and Leucoptera coffeella, the coffee leaf miner, infestation caused different responses in PPO activity in different Coffea species, level of damage or resistance, overview
-
-
?
additional information
?
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substrate specificity allows elucidation of a likely mechanism of aurone formation from 2,4,6,4-tetrahydroxychalcone or PHC involving both tyrosinase and catechol oxidase activities of the Antirrhinum majus PPO, pathway overview. Starting with THC, tyrosinase and catechol oxidase activity result in 3-hydroxylation and formation of the corresponding o-quinone. Besides aurone synthase PPO, a cytochrome P450 chalcone 3-hydroxylase is also involved in the 3-hydroxylation step
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?
additional information
?
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PPO is an enzyme concerning the o-hydroxylation of monophenols to o-diphenols acting as cresolase, EC 1.14.18.1, and the oxidation of o-diphenols to o-quinones acting as catecholase, EC 1.10.3.1
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?
additional information
?
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tyrosinase is known to be a key enzyme in melanin biosynthesis, involved in determining the color of mammalian skin and hair, various dermatological disorders, such as melasma, age spots and sites of actinic damage, arise from the accumulation of an excessive level of epidermal pigmentation
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?
additional information
?
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In Juglans regia, PPO is encoded by a single gene and has both catechol oxidase activity (oxidation of o-diphenols to their corresponding o-quinones, EC 1.10.3.1) and tyrosinase activity (hydroxylation of monophenols to o-diphenols, EC 1.14.18.1)
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?
additional information
?
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tyrosinases and catechol oxidases (EC 1.10.3.1) are members of the class of type III copper enzymes. While tyrosinases accept both mono- and o-diphenols as substrates, only the latter substrate is converted by catechol oxidases. The crystal structure reveals that the distinction between mono- and diphenolase activity does not depend on the degree of restriction of the active site, and thus a more important role for amino acid residues located at the entrance to and in the second shell of the active site is proposed
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?
additional information
?
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in Juglans regia, PPO is encoded by a single gene and has both catechol oxidase activity (oxidation of o-diphenols to their corresponding o-quinones, EC 1.10.3.1) and tyrosinase activity (hydroxylation of monophenols to o-diphenols, EC 1.14.18.1). The Larrea tridentate PPO gene product acts as a (+)-larreatricin 3'-hydroxylase in vivo
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?
additional information
?
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the PPO from Lonicera confusa exhibits both diphenolase and triphenolase activities, substrates monophenol (L-tyrosine), diphenols (L-DOPA, catechol, caffeic acid) and triphenols (pyrogallic acid, methyl gallate and gallic acid) are used by the enzyme
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?
additional information
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tyrosinases are able to catalyze the ortho-hydroxylation of monophenols to o-diphenols (monophenolase activity, EC 1.14.18.1) coupled with the subsequent two-electron oxidation of o-diphenols to the corresponding o-quinones (diphenolase activity, EC 1.10.3.1). The o-diphenols formed in the hydroxylation step remain in the active centre and are oxidized to the quinonic state. During the TYR mediated hydroxylation and oxidation of one molecule of monophenol, one molecule of dioxygen is reduced to water. Catechol oxidases, EC 1.10.3.1, lack the monophenolase activity and are thus only capable of oxidizing o-diphenols
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?
additional information
?
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tyrosinases are able to catalyze the ortho-hydroxylation of monophenols to o-diphenols (monophenolase activity, EC 1.14.18.1) coupled with the subsequent two-electron oxidation of o-diphenols to the corresponding o-quinones (diphenolase activity, EC 1.10.3.1). The o-diphenols formed in the hydroxylation step remain in the active centre and are oxidized to the quinonic state. During the TYR mediated hydroxylation and oxidation of one molecule of monophenol, one molecule of dioxygen is reduced to water. Catechol oxidases, EC 1.10.3.1, lack the monophenolase activity and are thus only capable of oxidizing o-diphenols
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additional information
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catalyzing the rate-limiting step for melanin biosynthesis
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?
additional information
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the enzyme plays a role in enzymatic browning, rapid discolouration of leaf, stem and root tissue after injury and strong pigmentation of tissue extracts, PPO and phenolic compounds could be an important part of the plants defence system against pests and diseases, including root parasitic nematodes, e.g. Radopholus similis
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?
additional information
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CATPO shows both catalase and phenol oxidase activities, its major activity is the catalase-mediated decomposition of hydrogen peroxide, but it also catalyzes peroxide-independent phenol oxidation
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?
additional information
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PPO activity is associated with color changes associated with browning and lycopene degradation, the commercial variety Naomi is more susceptible to enzymatic browning than the local varieties Pizzutello, Rosa Maletto and PO228, due to higher PPO activity levels, lycopene is an antioxidant agent that reconstitutes the polyphenols oxidized by the action of PPO
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additional information
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the partially purified enzyme has both cresolase and catecholase activity. Activity is lower toward monophenols than diphenols
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additional information
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polyphenol oxidase is a copper-containing enzyme that, in the presence of oxygen, catalyses the hydroxylation of monophenols to o-diphenols (cresolase activity) and the oxidation of o-diphenols to their corresponding o-quinones (catecholase activity)
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?
additional information
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polyphenoloxidases, PPOs, from Dornfelder and Riesling grapes display both monophenolase and diphenolase activity
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