|
type |
Journal Article |
authors |
Ueno, Y.; Hayakawa, K.; Takahashi, S.; Oda, K. |
title |
Purification and characterization of glutamate decarboxylase from Lactobacillus brevis IFO 12005 |
journal |
Biosci Biotechnol Biochem |
Activity |
4.1.1.15 |
ui |
97399889 |
year |
(1997) |
volume |
61 |
number |
7 |
pages |
1168-71. |
| |
keywords |
Amino Acid Sequence |
abstract |
Glutamate decarboxylase (GAD) [EC 4.1.1.15] was purified from a cell- free extract of Lactobacillus brevis IFO 12005 by chromatographies on Sephadex G-100, DEAE-Sepharose CL-6B, and Mono Q. About 9 mg of purified GAD was obtained from 90.2 g of wet cells. The purified preparation showed a single protein band on SDS-PAGE. The molecular weights of purified GAD by SDS-PAGE and gel filtration on Superdex 200 were 60,000 and 120,000, respectively, indicating that GAD from L. brevis exists as a dimer. The N-terminal amino acid sequence of the purified GAD was NH2-Met-Asn-Lys-Asn-Asp-Gln-Glu-Gln-Thr-. The optimum pH and temperature of GAD were at pH 4.2 and at 30 degrees C. The GAD activity was increased by the addition of sulfate ions in a dose- dependent manner. The order of effects was as follows: ammonium sulfate > sodium sulfate > magnesium sulfate, indicating that the increase of hydrophobic interaction between subunits causes the increase of GAD activity. The purified GAD reacted only with L-glutamic acid as a substrate and the K(m), kcat, and kcat/K(m) values were 9.3 mM, 6.5 S- 1, and 7 x 10(2) M-1 S-1, respectively. |
last changed |
2002/11/12 16:17 |
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