Method for producing gamma-glutamyl-valyl-glycine and/or a salt thereof

A method for producing gamma-glutamyl-valyl-glycine (γ-Glu-Val-Gly) and/or a salt thereof, comprising:

• adding γ-glutamylvaline synthetase and glutathione synthetase to a reaction mixture comprising Glu, Val, and Gly to react and produce γ-Glu-Val-Gly and/or salt thereof, and
• collecting the γ-Glu-Val-Gly and/or salt thereof,
• wherein the reaction mixture comprises ATP and a divalent metal ion,
• wherein the salt of γ-Glu-Val-Gly is at least one selected from the group consisting of a carboxylate salt, an ammonium salt, an alkali metal salt, an alkaline earth salt, an aluminum salt, a zinc salt, an organic amine salt, and a basic amino acid salt,
• wherein the γ-glutamylvaline synthetase and the glutathione synthetase are obtained from a modified Escherichia coli (E. coli) bacterium having
• an enhanced ability to produce γ-glutamylvalylglycine and/or the salt thereof compared to a non-modified bacterium,
• a deleted ybdK gene that encodes γ-glutamylglycine synthetase that is at least 90% identical to the amino acid sequence of SEQ ID NO:
• 16,
• a reduced γ-glutamylglycine synthetase activity compared to a non-modified bacterium,
• a deleted gshA gene that encodes a γ-glutamylcysteine synthetase that is at least 90% identical to the amino acid sequence of SEQ ID NO:
• 24,
• a reduced γ-glutamylcysteine synthetase activity compared to a non-modified bacterium,
• a deleted gene that encodes a γ-glutamyltransferase that is at least 90% identical to the amino acid sequence of SEQ ID NO:
• 26,
• a reduced γ-glutamyltransferase activity compared to a non-modified bacterium, and
• a gene encoding γ-glutamylvaline synthetase having an amino acid sequence that is at least 90% identical to the amino acid sequence of SEQ ID NO:
• 24 mutated with a substitution at a position selected from the group consisting of L135, Q144, Y241, N243, and Y300, or an amino acid sequence that is at least 90% identical to the amino acid sequence of SEQ ID NO:
• 18, 20, or 22, and
• wherein the γ-glutamylvaline synthetase has a ratio of γ-glutamylvaline synthetase activity to γ-glutamylglycine synthetase activity of at least 3.0.