|
|
| type |
Journal Article |
| authors |
Liu Q, Cheng H, Ma X, Xu N, Liu J, Ma Y |
| title |
Expression, characterization and mutagenesis of a novel glutamate decarboxylase from Bacillus megaterium |
| journal |
Biotechnol Lett |
| Activity |
4.1.1.15 |
| Family |
4.1.1.15.b |
| sel |
selected |
| ui |
26956237 |
| year |
(2016) |
| volume |
38 |
| number |
7 |
| pages |
1107-13 |
| | |
|---|
| keywords |
Bacillus megaterium; Gamma-aminobutyric acid (GABA); Glutamate decarboxylase (GAD); Mutagenesis |
| abstract |
OBJECTIVES:
To search for a novel glutamate decarboxylase (GAD) with an optimum pH towards near-neutrality in order to improve production of gamma-aminobutyric acid (GABA) in recombinant hosts.
RESULTS:
A novel glutamate decarboxylase, BmGAD, from Bacillus megaterium was overexpressed and purified. BmGAD was approximately 53 kDa by SDS-PAGE analysis. Its optimum activity was at pH 5 and 50 °C. BmGAD had a specific activity of 59 ± 5.2 U mg(-1) at pH 6, which is the highest value reported so far. The apparent Km and Vmax values of BmGAD were 8 ± 0.5 mM and 150 ± 4.7 U mg(-1), respectively. Through site-directed mutagenesis, two BmGAD mutants (E294R and H467A) showed higher Vmax values than that of wild-type, with the values of 210 ± 6.9 and 180 ± 4.1 U mg(-1) at pH 5 and 50 °C, respectively.
CONCLUSIONS:
The unusual high activity of BmGAD at pH 6 makes it an attractive GABA-producing candidate in industrial application. |
| last changed |
2017/10/11 09:00 |
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