Gelation of food protein induced by recombinant microbial transglutaminase

The recombinant microbial transglutaminase from Streptoverticillium mobaraense var. (rMTGase) was expressed in Escherichia coli. Specific enzyme activity of rMTGase was comparable to native MTGase. However, the gelation of a sodium caseinate solution induced by rMTGase was slower than that induced by native MTGase. In addition, the mechanical property of kamaboko prepared with rMTGase was weaker than that with native MTGase. In SDS-PAGE analysis, alpha-casein monomers decreased more slowly during the incubation with rMTGase than MTGase. These results confirmed the difference of cross-linking activity between the 2 enzymes. Furthermore, thermal stability of rMTGase was lower compared to native MTGase. These results suggest that the difference of cross-linking activity and thermal stability between the 2 enzymes cause differences in gelation activity of protein.