The present invention relates to a method of producing glutathione, wherein photosynthetic membrane vesicles and enzymes catalyzing glutathione synthesis are combined and glutamate, cysteine and glycine are used as reaction substrates. As enzymes catalyzing glutathione synthesis, γ-glutamylcysteine synthetase and glutathione synthetase may be used together, or bifunctional glutathione synthetase may be used alone. According to the conventional methods, there is a problem in that expensive adenosine triphosphate should be continuously supplied when glutathione is produced. However, according to the present invention, since photosynthetic membrane vesicles are used as a source to regenerate adenosine triphosphate, it is possible to continuously produce glutathione without additionally adding adenosine triphosphate, thereby reducing production costs of glutathione.

The present invention relates to a method of producing glutathione, wherein photosynthetic membrane vesicles and enzymes catalyzing glutathione synthesis are combined and glutamate, cysteine and glycine are used as reaction substrates. As enzymes catalyzing glutathione synthesis, γ-glutamylcysteine synthetase and glutathione synthetase may be used together, or bifunctional glutathione synthetase may be used alone. According to the conventional methods, there is a problem in that expensive adenosine triphosphate should be continuously supplied when glutathione is produced. However, according to the present invention, since photosynthetic membrane vesicles are used as a source to regenerate adenosine triphosphate, it is possible to continuously produce glutathione without additionally adding adenosine triphosphate, thereby reducing production costs of glutathione.

A microorganism useful as an expression host for γ-Glu-Val synthetase and a method for producing γ-Glu-Val-Gly using γ-Glu-Val synthetase expressed in the microorganism are provided. By using γ-Glu-Val synthetase expressed in a bacterium, such as Escherichia bacteria, modified so that the activity of a protein encoded by a ybdK gene (YBDIQ is reduced as an expression host, γ-Glu-Val-Gly is produced (Yom Glu, Val, and Gly as raw materials.

The present disclosure concerns a method for producing peptides such as glutathione and a microorganism that can be used for such method. One or more embodiments of the first aspect of the present disclosure concern a method for producing peptides such as glutathione comprising culturing a prokaryotic microbial strain in which the expression levels of one or more genes selected from among the gshA gene, the gshB gene, and the gshF gene are enhanced, compared with the expression levels thereof in the wild-type strain thereof in a medium in which the total concentration of cysteine and cystine is 0.5 g/l or lower. The second aspect of the present disclosure concerns a microorganism comprising disruptions of the γ-glutamyltransferase gene and the glutathione reductase gene and exhibiting the enhanced expression levels of the gshA gene and the gshB or gshF gene.

A mutant glutathione synthetase (GSHB) suitable for generating γ-Glu-Val-Gly, and a method for producing γ-Glu-Val-Gly using the same are provided. γ-Glu-Val-Gly is produced by using a mutant GSHB having a mutation at such a position as V7, N13, I14, N15, K17, F22, F95, M165, N199, Y200, P202, I274, T285, and P287.

A microorganism useful as an expression host for γ-Glu-Val synthetase and a method for producing γ-Glu-Val-Gly using γ-Glu-Val synthetase expressed in the microorganism are provided. By using γ-Glu-Val synthetase expressed in a bacterium, such as Escherichia bacteria, modified so that the activity of a protein encoded by a ybdK gene (YBDK) is reduced as an expression host, γ-Glu-Val-Gly is produced from Glu, Val, and Gly as raw materials.

The present invention relates to the technical field of biochemistry. Disclosed are a mutant enzyme, the use thereof and a process for preparing a tripeptide by using an enzymatic method. The mutant enzyme comprises: glycine and L-histidine ligase GHS, and tripeptide ligase HKS; or a fusion enzyme of the two. Glycine and L-histidine ligase activity is achieved by means of modifying an Lal enzyme, so as to obtain the GHS enzyme; and the ability for synthesizing dipeptide glycine-L-histidine and L-lysine is achieved by means of using a gshB enzyme, so as to obtain the HKS enzyme. On this basis, the GHS enzyme is further fused with the HKS enzyme by means of using a polypeptide chain, and then a bifunctional enzyme GHKS that links glycine, L-histidine and L-lysine in one step can be constructed, so that a tripeptide is conveniently prepared with a high yield. With regard to the large amount of ATP required in an enzymatic reaction, polyphosphate kinase can be used for cyclic regeneration, such that the amount of ATP is greatly reduced.

The present invention provides host cells for use in an inducible coexpression system that is capable of controlled induction of expression of each gene product.

The present invention provides host cells for use in an inducible coexpression system that is capable of controlled induction of expression of each gene product.

The present invention provides methods of producing thrombin using coordinated coexpression systems, and particularly inducible coexpression systems, capable of controlled induction of expression of each gene product required for the production of thrombin.