Glutamate decarboxylase (glutamate 1-carboxylyase, EC 4.1.1.15, GAD)* IS the major, rate-limiting enzyme in brain for synthesizing gamma-aminobutyric acid (GABA). Total GAD activity in brain is 10-20 times greater than the observed rate of GABA synthesis (Collins, 1972; Matsui and Deguchi, 1977; Casu and Gale, 1981), indicating that GAD operates at only a fraction of its capacity. Although othe...

This study aimed to enhance γ-aminobutyric acid (GABA) in pigeon pea milk (CCM). The drink was prepared from germinated and fermented using the probiotic Lactiplantibacillus plantarum Dad-13. Various nutrients significantly increased GABA content milk, i.e., sucrose 3% (4409 mg/L), monosodium glutamate (MSG) 1% (59,562 whey 4% (5283 respectively. Glutamate decarboxylase (GAD)-encoding genes wer...

1. The subcellular distributions of glutamate decarboxylase and aspartate transaminase were studied in rat and guinea-pig brain. 2. Glutamate decarboxylase is localized in the synaptosome fraction. The mean density of the particles containing the enzyme is slightly greater than those derived from cholinergic neurones, though overlap is substantial. 3. The enzyme is readily released from synapto...

Acid resistance (AR) in Escherichia coli is defined as the ability to withstand an acid challenge of pH 2.5 or less and is a trait generally restricted to stationary-phase cells. Earlier reports described three AR systems in E. coli. In the present study, the genetics and control of these three systems have been more clearly defined. Expression of the first AR system (designated the oxidative o...

Mouse brain glutamate decarboxylase(s) was specifically titrated in vivo and in crude brain homogenates by a combination of gabaculine and [a-'H]acetylenic yaminobutyric acid. This specific titration is based on the differential spectra of action of these two mechanism-based enzyme inactivators. The specificity of the titration in vitro was demonstrated by showing that the time course of radioa...

Ornithine decarboxylase (ODC) from Lactobacillus 30a catalyses the cleavage of alpha-methylornithine into ammonia and 2-methyl-1-pyrroline; glutamate decarboxylase (GAD) from Escherichia coli catalyses the cleavage of alpha-methylglutamate into ammonia and laevulinic acid. In our analyses, 2-methyl-1-pyrroline and laevulinic acid were identified by HPLC and mass spectroscopic analysis, and ammo...