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B6db references: 97399889

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
ui 97399889
year (1997)
volume 61
number 7
pages 1168-71.
keywords Amino Acid Sequence
abstract Glutamate decarboxylase (GAD) [EC] 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

B6db references