Transglutaminase

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Identifiers
EC number 2.3.2.13
CAS number Template:CAS
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum

A transglutaminase is an enzyme that catalyzes the formation of an isopeptide bond between a free amine group (e.g., protein- or peptide-bound lysine) and the acyl group at the end of the side chain of protein- or peptide-bound glutamine. The reaction also produces a molecule of ammonia. Such an enzyme is classified as EC 2.3.2.13. Bonds formed by transglutaminase exhibit high resistance to proteolytic degradation (proteolysis).

Transglutaminases were first described in 1959.[1] The exact biochemical activity of transglutaminases was discovered in blood coagulation protein factor XIII in 1968.[2]

Physiological transglutaminases

Eight transglutaminases have been characterised.[3]

Name Gene Activity Chromosome OMIM
Factor XIII (fibrin-stabilizing factor) F13A1, F13B coagulation 6p25-p24 134570
Keratinocyte transglutaminase TGM1 skin 14q11.2 190195
Tissue transglutaminase TGM2 ubiquitous 20q11.2-q12 190196
Epidermal transglutaminase TGM3 skin 20q12 600238
Prostate transglutaminase TGM4 prostate 3p22-p21.33 600585
TGM X TGM5[4] skin 15q15.2 603805
TGM Y TGM6 unclear 20q11-15 613900
TGM Z TGM7 testis, lung 15q15.2 606776
File:Transamidation and deamidation mechanisms of tissue transglutaminase.jpg
The upper reaction shows how a transaminase combines with a glutamine residue, releasing ammonia, and then the combination reacts with the amine group of a lysine residue of another protein, setting the enzyme free again.

Mechanism of action

Transglutaminases form extensively cross-linked, generally insoluble protein polymers. These biological polymers are indispensable for an organism to create barriers and stable structures. Examples are blood clots (coagulation factor XIII), as well as skin and hair.

The catalytic reaction is generally viewed as being irreversible, and must be closely monitored through extensive control mechanisms.[3] A collection of the transglutaminase substrate proteins and interaction partners is accessible in the TRANSDAB database.

Role in disease

Deficiency of factor XIII (a rare genetic condition) predisposes to hemorrhage; concentrated enzyme can be used to correct the abnormality and reduce bleeding risk.[3]

Anti-transglutaminase antibodies are found in celiac disease and may play a role in the small bowel damage in response to dietary gliadin that characterises this condition.[3] In the related condition dermatitis herpetiformis, in which small bowel changes are often found and which responds to dietary exclusion of gliadin-containing wheat products, epidermal transglutaminase is the predominant autoantigen.[5]

Recent research indicates that sufferers from neurological diseases like Huntington's[6] and Parkinson's[7] may have unusually high levels of one type of transglutaminase, tissue transglutaminase. It is hypothesized that tissue transglutaminase may be involved in the formation of the protein aggregates that causes Huntington's disease, although it is most likely not required.[3][8]

Mutations in keratinocyte transglutaminase are implicated in lamellar ichthyosis.

Industrial and culinary applications

File:GluedBistroTenders.jpg
Three bistro tenders being joined together with transglutaminase "meat glue". They will set overnight before being unwrapped, sliced into portions, cooked, and served.

In commercial food processing, transglutaminase is used to bond proteins together. Examples of foods made using transglutaminase include imitation crabmeat, and fish balls. It is produced by Streptoverticillium mobaraense fermentation in commercial quantities or extracted from animal blood,[9] and is used in a variety of processes, including the production of processed meat and fish products.

Transglutaminase can be used as a binding agent to improve the texture of protein-rich foods such as surimi or ham.[10]

Molecular gastronomy

Transglutaminase is also used in molecular gastronomy to meld new textures with existing tastes. Besides these mainstream uses, transglutaminase has been used to create some unusual foods. British chef Heston Blumenthal is credited with the introduction of transglutaminase into modern cooking.

Wylie Dufresne, chef of New York's avant-garde restaurant wd~50, was introduced to transglutaminase by Blumenthal, and invented a "pasta" made from over 95% shrimp thanks to transglutaminase.[11]

See also

References

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Additional sources

  • Lua error in package.lua at line 80: module 'strict' not found.
  • U.S. Patent 5,156,956 – A transglutaminase catalyzing an acyl transfer reaction of a Γ-carboxyamide group of a glutamine residue in a peptide or protein chain in the absence of Cz2+

External links