In silica analysis of gad gene presence in classic and next-generation probiotics

Gamma-aminobutyric acid (GABA) is primarily produced in microbes through a GAD enzyme-mediated decarboxylation of L-glutamate, with pyridoxal 5’- phosphate (PLP) as a co-factor (Yogeswara et al., 2020). While studies have focused on pathogenic bacteria, metagenomic analysis shows gut-colonising bacteria also encode the gad gene. The GAD enzyme, encoded by gadA, gadB, or both, mediates GABA synthesis in bacterial cells. Glutamate enters the cell via an antiporter channel for decarboxylation, and the final product, GABA, is secreted through a glutamate/GABA antiporter, encoded by the gadC gene .