Characterization of recombinant Zea mays transglutaminase expressed in Pichia pastoris and its impact on full and non-fat yoghurts.

BACKGROUND Transglutaminases catalyze post-translational modification of proteins by e-(γ-glutamyl) links and covalent amide bonds. Research on properties and applications of plant transglutaminases is less developed than in animals and micro-organisms. In a previous study, optimized Zea mays transglutaminase was purified from recombinant Pichia pastoris strain. The main objective of the present study was to characterize this enzyme and assess its effect on the properties of yoghurt. RESULTS The purified recombinant transglutaminase presented a Km of 3.98 µmol L−1 and a Vmax of 2711 min−1 by the fluorometric method. The enzyme was stable after incubation for 30 min below 50 °C and over a broad pH range of 5–8 at −20 °C for 12 h. The results showed that the crosslinking reaction catalyzed by this enzyme could effectively improve the properties of full and non-fat yoghurts. Also, the properties of non-fat yoghurt could be improved similar to the full-fat product by recombinant transglutaminase. CONCLUSION The application of recombinant transglutaminase in yoghurt indicated that this enzyme could be used as a substitute for microbial transglutaminase in the production of yoghurt, thus providing experimental evidence for the future application of plant transglutaminases in the food industry. © 2013 Society of Chemical Industry