ELI ROBINSON ON VIMR FREE
In this form of the complex, the conformation of tRNA/sup Glu/ is appreciably different from that of free molecule. The predominant form at low KCl concentration is closely related to the small K/sub m/ value for L-glutamate. In contrast, the heterologous tRNA/sup Glu/GluRS complex is in equilibrium of two forms that depends on KCl concentration. thermophilus tRNA/sup Glu/ upon complex formation with GluRS is not affected by addition of KCl. The circular dichroism analyses were made mainly of the bands due to the 2-thiouridine derivatives of tRNA/sup Glu/ in the complex. As the KCl concentration is raised from 0 to 100 mM, the K/sub m/ value for L-glutamate inmore » the heterologous system is remarkably increased whereas the K/sub m/ value for L-glutamate in the homologous system is only slightly increased. The KCl effects on the Michaelis constants (K/sub m/) for tRNA/sup Glu/, L-glutamate, and ATP were studied for the aminoacylation of the homologous tRNA/sup Glu/ and heterologous tRNA/sup Glu/ species. However, in the presence of E.coli tRNA/sup Glu/, GluRS binds specifically with L-glutamate. In the absence of tRNA/sup Glu/, GluRS binds with D- glutamate as well as L-glutamate. thermophilus tRNA/sup Glu/, Escherichia coli tRNA/sup Glu/, and amino acids was studied by fluorescence measurements. The binding of Thermus thermophilus glutamyl-tRNA synthetase ( GluRS) with T. Published by Elsevier B.V.Ĭonformation change of tRNA/sub Glu/ in the complex with glutamyl-tRNA synthetase is required for the specific binding of L-glutamate Finally, the maximum α-KG concentration reached 104.7g/ L from 110g/ L l-glutamic acid in 24h, under the following optimum conditions: 1.5U/m L LGOX, 250U/m L catalase, 3mM MnCl2, 30Â☌, and pH 6.5. Then the LGOX gene was expressed in Escherichia coli BL21 (DE3) in a soluble and active form, and the recombinant LGOX activity reached to a maximum value of 0.59U/m L at pH 6.5, 30Â☌. First, by analyzing the molecular structure characteristics of l-glutamic acid and α-KG, LGOX was found to be the best catalyst for oxidizing the amino group of l-glutamic acid to a ketonic group without the need for exogenous cofactor.
In this study, a novel strategy for α-ketoglutaric acid (α-KG) production from l-glutamic acid using recombinant l-glutamate oxidase (LGOX) was developed. Niu, Panqing Dong, Xiaoxiang Wang, Yuancai Liu, Liming
L-PGA protects cortical neurons against Glu-induced neurotoxity which may be related to inhibition of NO formation or suppression of the rise in i.Įnzymatic production of α-ketoglutaric acid from l-glutamic acid via l-glutamate oxidase.
L-PGA also attenuated Glu-induced NO release. L-1)-induced neuronal loss in a concentration-dependent manner with IC50 value of (41 +/- 9) mumol. In primary cortical cultures from 16-d-old fetal rat, neuronal viability and contents of nitrite in the bathing medium after transient exposure to sodium glutamate ( Glu) were measured with Fura 2-AM as an intracellular calcium indicator, AR-CM-MIC cation measurement system was used to examine cytosolic free calcium (i). To evaluate the effects of L-pyroglutamic acid ( L-PGA, L-5-oxo-2-pyrrolidinecaroxylic acid) on sodium glutamate-induced neurotoxicity in rat cortical neurons. L-pyroglutamic acid protects rat cortical neurons against sodium glutamate-induced injury.
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