Microbial Transglutaminase

Microbial transglutaminase (MTG, synonymous with BTG for bacterial transglutaminase) was
discovered by the Japanese companies Amano Enzyme® and Ajinomoto® in the late 1980s by screening 5,000 microorganisms. The aim was to identify a constant supply of a cheap and stable transglutaminase for food applications.

The microorganism Streptomyces mobaraensis (formerly known as Streptoverticillium mobaraense) produces a calcium-independent transglutaminase with the desired properties. MTG is produced as an inactive proenzyme and is secreted to the fermentation broth. Subsequently, proteolytic cleavage of the 45 amino acid propeptide yields active MTG.

MTG is produced at the industrial scale and is marketed by Ajinomoto® under the brand Activa®. Using different formulations, the enzyme is widely used to modulate the texture and properties of protein-containing food. Also, innovative non-food applications using protein cross-linking have been described.
An overview of the properties and applications of MTG is given by Keiichi Yokoyama, Noriki Nio and Yoshimi Kikuchi in: "Properties and applications of microbial transglutaminase", Appl. Microbiol. Biotechnol. 2004, 64:447-54.

The physiological function of microbial transglutaminase, activating proteases and substrates has been summarized by Alla Sarafeddinov, Atia Arif, Anna Peters and Hans-Lothar Fuchsbauer in: “A Novel Transglutaminase Substrate from Streptomyces mobaraensis Inhibiting Papain-Like Cysteine Proteases”, J. Microbiol. Biotechnol. 2011, 21:617–26.

Scientists at Zedira developed a proprietary recombinant production method yielding pure and highly active enzymes marketed as Andracon® (T250 and T300). In addition, we offerconvenient microbial transglutaminase assay kits for quality control for the food industry and academia (Z009, M001). However, microbial transglutaminase is much more than biotechnological glue. Due to the broad substrate acceptance, the purified enzyme can also be used for site-specific protein modification like labeling or pegylation (see section 7: Transglutaminase labeling). Finally, Zedira provides a specific inhibitor (MTG-Blocker, C102) to control the course of the reaction.

Zedira’s MTG-Handbook provides an overview of this fascinating enzyme.