Study on Catalytic Mechanism of Microbial Transglutaminase in Protein Substrate

Abstract

Transglutaminase (abbreviated as TG,EC2.3.2.13) can catalyze the acyl transfer reaction of peptides in protein, but it can only catalyze a certain acyl transfer reaction instead of every acyl group. Protein is widely used to modify protein in food industry because it is safe and non-toxic and the catalyzed product can be digested and absorbed by human body. In this paper, the catalytic mechanism of protein substrate for MTG (Microbial TG) was studied in order to provide theoretical basis for the follow-up research and application of MTG. The results show that within 1%~4%, the total amount of biopolymer produced increases linearly, and then it remains basically unchanged. The catalytic amount of MTG to substrate and catalytic efficiency are contradictory. Under the condition of fixed MTG concentration, the higher the substrate concentration, the smaller the catalytic efficiency, and it shows a linear downward trend. When the concentration is 10%, the gel strength is the highest, reaching 68.09g. When the concentration of protein is low, protein-solvent interaction is dominant, and the system is not easy to form gel. The lower the hydrophobicity of protein surface, the easier it is to be catalyzed by MTG. However, the surface hydrophobicity of soybean globulin is in the middle, and MTG has moderate catalytic activity for it.