Tyrosinase: Difference between revisions

From WikiMD's Wellness Encyclopedia

Newer edit →
CSV import
 
CSV import
Line 1: Line 1:
'''Tyrosinase''' is an [[enzyme]] that is involved in the production of [[melanin]] and other pigments from [[tyrosine]] by oxidation. It is found in a wide variety of organisms, including humans, animals, plants, and fungi. Tyrosinase is a copper-containing enzyme that catalyzes several reactions in the melanin synthesis pathway.
== Tyrosinase ==
 
'''Tyrosinase''' is an enzyme that is involved in the production of melanin and other pigments from [[tyrosine]] by oxidation. It is a copper-containing enzyme found in plants, animals, and fungi, and is responsible for browning in damaged fruits and vegetables.
 
== Structure ==
Tyrosinase is a type 3 copper protein, meaning it contains two copper ions that are coordinated by histidine residues. The enzyme is typically a monomer, but can also form dimers or higher oligomers. The active site of tyrosinase is highly conserved across different species.


== Function ==
== Function ==
Tyrosinase carries out the oxidation of phenols such as tyrosine and dopamine using dioxygen (O2). In humans, tyrosinase is sorted into melanosomes and the catalytically active domain of the protein resides within melanosomes. Only a small, enzymatically inessential part of the protein extends into the cytoplasm of the melanocyte.
Tyrosinase catalyzes the oxidation of phenols such as tyrosine to quinones, which are precursors to melanin. The enzyme has two main activities: the hydroxylation of monophenols (monophenolase activity) and the oxidation of o-diphenols to o-quinones (diphenolase activity).


== Clinical significance ==
== Biological Role ==
Mutations in the tyrosinase gene result in [[oculocutaneous albinism]] type 1 (OCA1), a disorder characterized by a reduction or complete loss of melanin pigment in the skin, hair, and eyes. OCA1 is the most severe type of albinism and is the most common form worldwide.
In humans, tyrosinase is crucial for the production of melanin, which determines the color of skin, hair, and eyes. Mutations in the tyrosinase gene can lead to conditions such as [[albinism]], where melanin production is impaired.


== Structure ==
== Industrial and Medical Applications ==
The three-dimensional structure of tyrosinase reveals that the protein is a dimer, with each monomer containing a binuclear, type 3 copper centre. The copper ions are coordinated by six histidine residues in the active site.
Tyrosinase is used in various industrial applications, including the development of biosensors and in the food industry to prevent browning. In medicine, tyrosinase inhibitors are being researched for their potential in treating hyperpigmentation disorders.
 
== Related Enzymes ==
Tyrosinase is part of the [[polyphenol oxidase]] family, which also includes catechol oxidase and laccase. These enzymes share similar substrates and mechanisms but differ in their specific activities and roles.


== See also ==
== Related Pages ==
* [[Melanin]]
* [[Melanin]]
* [[Oculocutaneous albinism]]
* [[Albinism]]
* [[Tyrosine]]
* [[Polyphenol oxidase]]


== References ==
== References ==
<references />
* Solomon, E. I., Sundaram, U. M., & Machonkin, T. E. (1996). Multicopper oxidases and oxygenases. Chemical Reviews, 96(7), 2563-2605.
* Hearing, V. J. (2011). Determination of melanin synthetic pathways. Journal of Investigative Dermatology, 131(E1), E8-E11.
 
== Gallery ==
<gallery>
File:PPO_figure.jpeg|Diagram of polyphenol oxidase activity.
File:Catechol-Quinone.svg|Chemical structure of catechol and quinone.
File:PDB_1js8_EBI.jpg|Crystal structure of tyrosinase.
File:Protein_nucleotides.png|Representation of protein and nucleotide interaction.
File:Mason_raper_pathway.png|Mason-Raper pathway of melanin synthesis.
File:Tyrosinase_phylogeny.png|Phylogenetic tree of tyrosinase.
File:Drawing_of_ORF_with_mutations_updated.png|Open reading frame with mutations.
File:Substituted_amino_acids_of_tyrosinase_in_albino_frogs.png|Substituted amino acids in albino frogs.
File:Tyrosinase_Human_Exon-Intron_Representation.png|Exon-intron structure of human tyrosinase.
File:Consurf_tyrosinase_protein.png|ConSurf analysis of tyrosinase protein.
</gallery>


[[Category:EC 1.14.18]]
[[Category:Human proteins]]
[[Category:Enzymes]]
[[Category:Enzymes]]
 
[[Category:Oxidoreductases]]
{{stub}}

Revision as of 00:35, 10 February 2025

Tyrosinase

Tyrosinase is an enzyme that is involved in the production of melanin and other pigments from tyrosine by oxidation. It is a copper-containing enzyme found in plants, animals, and fungi, and is responsible for browning in damaged fruits and vegetables.

Structure

Tyrosinase is a type 3 copper protein, meaning it contains two copper ions that are coordinated by histidine residues. The enzyme is typically a monomer, but can also form dimers or higher oligomers. The active site of tyrosinase is highly conserved across different species.

Function

Tyrosinase catalyzes the oxidation of phenols such as tyrosine to quinones, which are precursors to melanin. The enzyme has two main activities: the hydroxylation of monophenols (monophenolase activity) and the oxidation of o-diphenols to o-quinones (diphenolase activity).

Biological Role

In humans, tyrosinase is crucial for the production of melanin, which determines the color of skin, hair, and eyes. Mutations in the tyrosinase gene can lead to conditions such as albinism, where melanin production is impaired.

Industrial and Medical Applications

Tyrosinase is used in various industrial applications, including the development of biosensors and in the food industry to prevent browning. In medicine, tyrosinase inhibitors are being researched for their potential in treating hyperpigmentation disorders.

Related Enzymes

Tyrosinase is part of the polyphenol oxidase family, which also includes catechol oxidase and laccase. These enzymes share similar substrates and mechanisms but differ in their specific activities and roles.

Related Pages

References

  • Solomon, E. I., Sundaram, U. M., & Machonkin, T. E. (1996). Multicopper oxidases and oxygenases. Chemical Reviews, 96(7), 2563-2605.
  • Hearing, V. J. (2011). Determination of melanin synthetic pathways. Journal of Investigative Dermatology, 131(E1), E8-E11.

Gallery

  • Diagram of polyphenol oxidase activity.
    Diagram of polyphenol oxidase activity.
  • Chemical structure of catechol and quinone.
    Chemical structure of catechol and quinone.
  • Crystal structure of tyrosinase.
    Crystal structure of tyrosinase.
  • Representation of protein and nucleotide interaction.
    Representation of protein and nucleotide interaction.
  • Mason-Raper pathway of melanin synthesis.
    Mason-Raper pathway of melanin synthesis.
  • Phylogenetic tree of tyrosinase.
    Phylogenetic tree of tyrosinase.
  • Open reading frame with mutations.
    Open reading frame with mutations.
  • Substituted amino acids in albino frogs.
    Substituted amino acids in albino frogs.
  • Exon-intron structure of human tyrosinase.
    Exon-intron structure of human tyrosinase.
  • ConSurf analysis of tyrosinase protein.
    ConSurf analysis of tyrosinase protein.
Retrieved from "https://wikimd.com/index.php?title=Tyrosinase&oldid=6201427"