type	Journal Article
authors	Sa HD, Park JY, Jeong SJ, Lee KW, Kim JH
title	Characterization of Glutamate Decarboxylase (GAD) from Lactobacillus sakei A156 Isolated from Jeot-gal
journal	J Microbiol Biotechnol
Activity	4.1.1.15
Family	4.1.1.15.b
sel	selected
ui	25791853
year	(2015)
volume	25
number	5
pages	696-703
keywords	Abs, absorbance; BmGadB, Brucella microti GadB; Brucella microti; Chloride activation; Cooperativity; EcGadB, Escherichia coli GadB; GABA, γ-aminobutyrate; GDAR, glutamate-dependent acid resistance; GadB, glutamate decarboxylase (B isoform); Glutamate decarboxylase; PLP, pyridoxal 5′-phosphate; Substituted aldamine; pH-dependent activity.
abstract	A gamma-aminobutyric acid (GABA)-producing microorganism was isolated from jeot-gal (anchovy), a Korean fermented seafood. The isolate, A156, produced GABA profusely when incubated in MRS broth with monosodium glutamate (3% (w/v)) at 37°C for 48 h. A156 was identified as Lactobacillus sakei by 16S rRNA gene sequencing. The GABA conversion yield was 86% as determined by GABase enzyme assay. The gadB gene encoding glutamate decarboxylase (GAD) was cloned by PCR. gadC encoding a glutamate/GABA antiporter was located immediately upstream of gadB. The operon structure of gadCB was confirmed by RT-PCR. gadB was overexpressed in Escherichia coli BL21(DE3) and recombinant GAD was purified. The purified GAD was 54.4 kDa in size by SDS-PAGE. Maximum GAD activity was observed at pH 5.0 and 55°C and the activity was dependent on pyridoxal 5'-phosphate. The Km and Vmax of GAD were 0.045 mM and 0.011 mM/min, respectively, when glutamate was used as the substrate.
last changed	2017/10/10 13:39