Enzymatic production of γ-aminobutyric acid in soybeans using high hydrostatic pressure and precursor feeding

Shigeaki Ueno, Takumi Katayama, Takae Watanabe, Kanako Nakajima, Mayumi Hayashi, Toru Shigematsu, Tomoyuki Fujii

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


The effects were investigated of the glutamic acid (Glu) substrate concentration on the generation and kinetics of γ-aminobutyric acid (GABA) in soybeans treated under high hydrostatic pressure (HHP; 200MPa for 10 min at 25 °C). The conversion of Glu to GABA decreased with increasing initial Glu concentration in the soybeans. The crude glutamate decarboxylase (GAD) obtained from the HHP-treated soybeans showed substrate inhibition. The GABA production rate in the HHPtreated soybeans fitted the following substrate inhibition kinetic equation: v0 =(VmaxS0)/(Km+ S0 + (S0)2/Ki). The Km value for the HHP-treated soybeans was significantly higher than that of the untreated soybeans. The Km values in this study show the affinity between Glu and GAD, and indicate that the HHP-treated soybeans had lower affinity between Glu and GAD than the untreated soybeans. GAD extracted from the HHPtreated soybeans showed a similar value to that in the HHP-treated soybeans. The intact biochemical system was so damaged in the HHP-treated soybeans that it showed substrate inhibition kinetics similar to that of the extracted GAD. The combination of HHP and precursor feeding proved to be a novel tool that can be used to increase the concentration of a target component.

Original languageEnglish
Pages (from-to)706-713
Number of pages8
JournalBioscience, Biotechnology and Biochemistry
Issue number4
Publication statusPublished - 2013


  • Free amino acid
  • Glutamate decarboxylase
  • High hydrostatic pressure
  • Soybean
  • γ-aminobutyric acid


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