Exchange of glutamate and gamma-aminobutyrate in a Lactobacillus strain

Lactobacillus sp. strain El catalyzed the decarboxylation of glutamate (Glu), resulting in a nearly stoichiometric release of the products gamma-aminobutyrate (GABA) and CO2. This decarboxylation was associated with the net synthesis of ATB. ATP synthesis was inhibited almost completely bg nigericin and about 70% by N,N'-dicyclohexylcarbodiimide (DCCP), without inhibition of the decarboxylation. These findings are consistent with the possibility that a proton motive force arises from the cytoplasmic proton consumption that accompanies glutamate decarboxylation and the electrogenic Glu/GABA antiporter and the possibility that this proton motive force is coupled with ATP synthesis by DCCD-sensbtive ATPase.