Microbial Transglutaminase

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

The microorganism Streptomyces mobaraensis (formerly known as Streptoverticillium mobaraense) turned out to produce 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 in 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 on 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 recently 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 enzyme (T250 and T300). In addition we market convenient microbial transglutaminase assay kits for quality control in 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 reaction.

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