- Molecular cloning and characterization of γ-Glutamyltranspeptidase from pseudomonas nitroreducens IFO12694
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y-Glutamyltranspeptidase from Pseudomonas nitroreducens IFO12694 (PnGGT) exhibited higher hydro-lytic activity than transfer activity, as compared with other y-glutamyltranspeptidases (GGTs). PnGGT showed little activity towards most of L-amino acids and towards glycyl-glycine, which is often used as a standard y-glutamyl accepter in GGT transfer reactions. The preferred substrates for PnGGT as a y-glutamyl accepter were amines such as methylamine, ethylamine, and isopropylamine.
- Imaoka, Masashi,Yano, Shigekazu,Okumura, Masashi,Hibi, Takao,Wakayama, Mamoru
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experimental part
p. 1936 - 1939
(2011/06/11)
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- Characterization of theanine-forming enzyme from Methylovorus mays No. 9 in respect to utilization of theanine production
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For development of theanine production from glutamic acid and ethylamine by coupling yeast sugar fermentation as an ATP-regenerating system, several strains were selected from among about 200 methylamine- and/or methanol-assimilating bacteria depending on the theanine-forming activity of their permeated cells. The amount of theanine formed by the cells of the selected strains was much larger than that by the cells of Escherichia coli AD494 (DE3) expressing Pseudomonas taetrolens Y-30 glutamine synthetase (GS), which has been found to be a usable enzyme for theanine production. A GS-like enzyme responsible for the theanine-forming reaction was obtained from an obligate methylotroph isolate, Methylovorus mays No. 9. The enzyme was induced by methylamine in the culture medium. A molecular mass of 410-470 kDa was obtained by gel filtration of the enzyme, and 51 kDa by SDS-PAGE analysis. The enzyme showed high activity toward methylamine rather than ammonia, which indicates that it is similar to known γ-glutamylmethylamide synthetase. The isolated enzyme also had high reactivity to ethylamine in a neutral pH range, and formed theanine from glutamic acid and ethylamine in a reaction mixture containing a yeast sugar fermentation system for ATP-regeneration.
- Yamamoto, Sachiko,Wakayama, Mamoru,Tachiki, Takashi
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p. 545 - 552
(2008/03/27)
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- γ-Glutamyl Transfer Reactions by Glutaminase from Pseudomonas nitroreducens IFO 12694 and Their Application for the Syntheses of Theanine and γ-Glutamylmethylamide
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In a mixture containing γ-glutamyl donor (donor) and γ-glutamyl acceptor (acceptor), the glutaminase of Pseudomonas nitroreducens IFO 12694 simultaneously catalyzed a γ-glutamyl transfer reaction and hydrolysis of the donor. The variation of the activities responding to the concentration of glutathione and glycylglycine indicated that the enzyme might be classified in a group of glutaminases that shows hydrolysis prior to transfer reaction. On the other hand, the results with glutamine and ethylamine or methylamine indicated that the enzyme was active in the transfer reaction with suppressed hydrolysis of glutamine, and suggested the possibility of using the reaction for producing γ-glutamylethylamide (theanine) or γ-glutamylmethylamide (γ-GMA). In fact, in a mixture containing high concentrations of substrates (0.7 M glutamine, 1.5 M ethylamine or methylamine) and 0.5 unit/ml glutaminase (borate buffer pH 11), 270 mM (47 g/L) theanine or 250 mM (38 g/L) γ-GMA was formed in 7 h of incubation at 30°C.
- Tachiki, Takashi,Yamada, Takeshi,Mizuno, Katsushige,Ueda, Masashi,Shiode, Ju-Ichi,Fukami, Hiroshi
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p. 1279 - 1283
(2007/10/03)
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- Drug Latentiation by γ-Glutamyl Transpeptidase
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The N-γ-glutamyl derivatives of L-thiazolidine-4-carboxylic acid, 4-aminobutyric acid, 1-aminocyclopentanecarboxylic acid, 2-aminophenol, and p-fluoro-L-phenylalanine (compounds 6, 8, 9, 10, and 12 respectively) were synthesized using the synthom phthaloylglutamic anhydride.Their relative rates of cleavage by the enzyme γ-glutamyl transpeptidase (γ-GT) were determined in order to evaluate the possibility for their selective release by this enzyme which is elevated in certain pathological conditions.Compounds 6, 8, and 9 were not readily solvolyzed by γ-GT, but compounds 10 and 12, as well as the N-γ-glutamylated derivatives of 3- and 4-aminophenol, were readily cleaved.
- Magnan, Sanne D. J.,Shirota, Frances N.,Nagasawa, Herbert T.
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p. 1018 - 1021
(2007/10/02)
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