Thermostable difunctional glutathione synthetase mutant and application thereof

The invention discloses a mutant of difunctional glutathione synthetase. The mutant is an amino acid sequence as shown in SEQ ID NO.3 or a mutant thereof obtained by recombining amino acid sequences as shown in SEQ ID NO.2 and SEQ ID NO.1 and/or carrying out site-directed mutagenesis on a recombinant. The mutant has the advantages that the thermal stability of the mutant is remarkably improved, and the half-life period t1/2 is 10-60 times that of wild enzyme. The half-life period t1/2 of the optimal mutant is 163.3 times that of the wild enzyme, and the specific enzyme activity is improved by 24% compared with that of the wild enzyme. Compared with the temperature of the wild enzyme, the optimal temperature of the optimal mutant is increased from 45 DEG C to 50 DEG C. Tests such as enzyme catalysis, intracellular self-assembly whole-cell catalysis and fermentation prove that the finally obtained mutant effectively improves the yield and synthesis efficiency of GSH. 本发明公开一种双功能谷胱甘肽合成酶的突变体，所述突变体为将SEQ ID NO.2和SEQ