Functional Modification of Protein-glutaminase and its Industrial Application

Functional Modification of Protein-glutaminase and its Industrial Application

Kazunori Yoshida, Kiyota Sakai, Satoru Ishihara, Shotaro Yamaguchi

 Amano Enzyme Inc. 1-6, Technoplaza, Kakamigahara-Shi, Gifu 509-0109 JAPAN

kazunori_yoshida@amano-enzyme.com

Frontier Research Department

Abstract: Within the food industry, there are challenges to improve the solubility and emulsification properties of plant-based food proteins. With the help of Protein-glutaminase (EC 3.5.1.44) (PG), Amano Enzyme Inc. have developed various PG mutants with improved enzyme function. PG is an enzyme that deamidates the amide groups of glutamic acid residues in food proteins. In this presentation, the aim is to focus on PG mutant to improve high-temperature reactivity. PG from Chryseobacterium proteolyticum (Appl. Environ. Microbial., 66, 3337 (2000); Eur. J. Biochem., 268, 1410 (2001)) (PG-WT) was modified by protein engineering that combination of de novo design and random mutagenesis. PG activity was evaluated by the amount of ammonia released from Z-Gln-Gly (synthetic peptide) or natural protein. PG mutant (PG-MT) was obtained that it has more than 5-fold higher reactivity at 70°C than PG-WT. Additionally, reactivity of natural protein such as casein, soy, pea, etc... were not changed. PG-MT has the highest high-temperature reactivity among the currently reported protein glutaminase. In summary, PG-MT application has proven to have the best results and the potential to introduce this technology to plant-based food industry. With various versatile enzymes that Amano enzyme Inc. has to offer and with the combination of innovative technology, PG-MT can overcome challenges in plant-based food applications.

 Keywords: protein-glutaminase; enzyme function modification; protein engineering; high-temperature reactivity; plant-based food