Glutamine transaminase mutant with improved enzymatic activity

Abstract

The invention discloses a glutamine transaminase mutant with improved enzymatic activity, which belongs to the field of enzyme engineering. The site-specific mutagenesis is performed on glutamine transaminase, an amino acid residue close to an active site of the glutamine transaminase is changed, so that the catalytic efficiency of the glutamine transaminase is improved, and the enzymatic activityof the glutamine transaminase is further improved. Recombinant yarrowia lipolytica with improved enzymatic activity is established by the glutamine transaminase mutant, the enzymatic activity of theglutamine transaminase is improved by 1.45 times compared with an original strain, the enzymatic activity of the shake flask fermentation can reach 16.995U / mL, and the enzymatic activity of the fermenting tank fermentation can reach 59.85U / mL which is the highest fermentation value reported at present.

Description

technical field

[0001] The invention relates to a glutamine transaminase mutant with improved enzyme activity, and belongs to the field of enzyme engineering. Background technique

[0002] Glutamine transaminase (Transglutaminase, EC 2.3.2.13, TGase) can catalyze the transacylation reaction between the γ-carboxamide group in the glutamine residue in the peptide chain and the acyl acceptor, so that the protein or polypeptide can interact with each other. Covalent cross-linking. TGase is widely used in the field of food processing. For example, TGase can cross-link proteins with essential amino acids (such as lysine) to improve the nutritional value of some foods. TGase can bond minced meat into pieces, improve the utilization rate of meat products, and improve the elasticity of meat products. In addition, TGase has huge market demand in the fields of medicine, cosmetics, biotechnology research, textile industry and leather processing.

[0003] Originally, TGase was derived...

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