Nutrition Guide

A deficiency in any of the enzymes of this complex as well as an inhibition of the complex as a whole is responsible for maple syrup urine disease.

This enzyme is an autoantigen recognized in primary biliary cirrhosis, a form of acute liver failure. These antibodies appear to recognize oxidized protein that has resulted from inflammatory immune responses. Some of these inflammatory responses are explained by gluten sensitivity.[1]. Other mitochondrial autoantigens include pyruvate dehydrogenase and branched chain oxoglutarate dehydrogenase, which are antigens recognized by anti-mitochondrial antibodies.

This complex is also analogous to the alpha-ketoglutarate dehydrogenase complex in the citric acid cycle and the pyruvate dehydrogenase complex creating acetyl-CoA prior to the citric acid cycle.

This complex requires the following 5 cofactors:
Thiamine diphosphate
FAD
NAD+
Lipoate
Coenzyme A

The branched-chain ?-keto acid dehydrogenase complex is a combination of enzymes responsible for the degradation of the branched chain amino acids. Examples of these include valine, isoleucine, and leucine.

Industrial transglutaminase is produced by Streptomyces mobaraensis fermentation in commercial quantities and is used in a variety of processes, including the production of processed meat and fish products. It can be used as a binding agent to improve the texture of protein-rich foods such as surimi or ham.[9] Transglutaminase can be used in these applications:[citation needed] Binding small chunks of meats into a big one (”portion control”), such as in sausages, hot dogs, restructured steaks Improving the texture of low-grade meat such as so-called “PSE meat” (pale, soft, and exudative meat, whose characteristics are attributed to stress and a rapid postmortem pH decline) Making milk and yogurt creamier Making noodles firmer Besides these mainstream uses, transglutaminase has been used to create some unusual foods. British chef Heston Blumenthal is credited with the introduction of “meat glue” 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 by over 95% shrimps thanks to transglutaminase.[10]

Transglutaminases form extensively cross-linked, generally insoluble protein polymers. These biological polymers are indispensable for the organism in order 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.

Transglutaminases are a family of enzymes (EC 2.3.2.13) that catalyze the formation of a covalent bond between a free amine group (e.g., protein- or peptide-bound lysine) and the gamma-carboxamid group of protein- or peptide-bound glutamine. Bonds formed by transglutaminase exhibit high resistance to proteolytic degradation.

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

Serology for anti-tTG antibodies has superseded older serological tests (anti-endomysium, anti-gliadin and anti-reticulin) and has a strong sensitivity (99%) and specificity (>90%) for identifying coeliac disease. Modern anti-tTG assays rely on a human recombinant protein as an antigen

Tissue transglutaminase is best known for its link with coeliac disease. Anti-transglutaminase antibodies (ATA) result in a form of gluten sensitivity in which a cellular response to Triticeae glutens that are crosslinked to tTG are able to stimulate transglutaminase specific B-cell responses that eventually result in the production of ATA IgA and IgG.[6]

Recent studies suggest that tTG plays a role in inflammation, degenerative diseases and tumor biology.[1]

tTG is expressed ubiquitously. It requires calcium as a cofactor for transamidation activity. Transcription is increased by retinoic acid. Amongst its many supposed functions, it appears to play a role in wound healing, apoptosis and extracellular matrix development[1]

TG2 also has GTPase activity: in the presence of GTP it suggested to function as a G protein participating in signaling processes.[2] Beside its transglutaminase activity, TG2 is proposed to also act as kinase,[3] and protein disulfide isomerase,[4] and deamidase.[5] This latter activity is important in the deamidation of gliadin peptides thus playing important role in the pathology of coeliac disease.