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Tomonori Unno - One of the best experts on this subject based on the ideXlab platform.
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Theanine, gamma-glutamylethylamide, is metabolized by renal phosphate-independent glutaminase.
Biochimica et biophysica acta, 2003Co-Authors: Haruhito Tsuge, Sachi Sano, Takashi Hayakawa, Takami Kakuda, Tomonori UnnoAbstract:The distribution of Theanine-degrading activity in Wistar rats was examined and this activity was detected only in the kidney. Judging from polyacrylamide gel electrophoresis, Theanine-degrading enzyme from rat kidney was purified almost to homogeneity. Theanine-degrading activity was co-purified with glutaminase activity, and the relative activity for Theanine was about 85% of that for L-glutamine throughout purification. Substrate specificity of purified enzyme preparation coincided well with the data of phosphate-independent glutaminase [EC 3.5.1.2], which had been previously reported. It was very curious that gamma-glutamyl methyl and ethyl esters were more effectively hydrolyzed than Theanine and L-glutamine, in view of relative activity and K(m) value. It was suggested that gamma-glutamyl moiety in Theanine molecule was transferred to form gamma-glutamylglycylglycine with relative ease in the presence of glycylglycine. On the other hand, purified phosphate-dependent glutaminase did not show Theanine-degrading activity at all. Thus, it was concluded that Theanine was hydrolyzed by phosphate-independent glutaminase in kidney and suggested that, as for the metabolic fate of Theanine, its glutamyl moiety might be transferred by means of gamma-glutamyl transpeptidase reaction to other peptides in vivo.
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Theanine, γ-glutamylethylamide, is metabolized by renal phosphate-independent glutaminase
Biochimica et Biophysica Acta, 2002Co-Authors: Haruhito Tsuge, Sachi Sano, Takashi Hayakawa, Takami Kakuda, Tomonori UnnoAbstract:Abstract The distribution of Theanine-degrading activity in Wistar rats was examined and this activity was detected only in the kidney. Judging from polyacrylamide gel electrophoresis, Theanine-degrading enzyme from rat kidney was purified almost to homogeneity. Theanine-degrading activity was co-purified with glutaminase activity, and the relative activity for Theanine was about 85% of that for l -glutamine throughout purification. Substrate specificity of purified enzyme preparation coincided well with the data of phosphate-independent glutaminase [EC 3.5.1.2], which had been previously reported. It was very curious that γ-glutamyl methyl and ethyl esters were more effectively hydrolyzed than Theanine and l -glutamine, in view of relative activity and K m value. It was suggested that γ-glutamyl moiety in Theanine molecule was transferred to form γ-glutamylglycylglycine with relative ease in the presence of glycylglycine. On the other hand, purified phosphate-dependent glutaminase did not show Theanine-degrading activity at all. Thus, it was concluded that Theanine was hydrolyzed by phosphate-independent glutaminase in kidney and suggested that, as for the metabolic fate of Theanine, its glutamyl moiety might be transferred by means of γ-glutamyl transpeptidase reaction to other peptides in vivo.
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Metabolism of Theanine, gamma-glutamylethylamide, in rats.
Journal of agricultural and food chemistry, 1999Co-Authors: Tomonori Unno, Takami Kakuda, Takashi Hayakawa, Yuko Suzuki, Haruhito TsugeAbstract:The metabolism of Theanine, one of the major amino acid components in tea (Camellia sinensis), was studied in rats. High-performance liquid chromatography (HPLC) with fluorometric detection was used to evaluate the nature of Theanine's metabolites in plasma, urine, and tissues. In the urine samples collected after administration of 100, 200, and 400 mg each of Theanine, intact Theanine, L-glutamic acid, and ethylamine, these compounds were detected in a dose-dependent manner. When 200 mg of Theanine was orally administered to rats, the plasma concentrations of Theanine and ethylamine reached their highest levels about 0.5 and 2 h after administration, respectively. It seems most likely that the enzymatic hydrolysis of Theanine to glutamic acid and ethylamine was accomplished in the kidney. These results indicate that orally administered Theanine is absorbed through the intestinal tract and hydrolyzed to glutamic acid and ethylamine in the rat kidney.
Takami Kakuda - One of the best experts on this subject based on the ideXlab platform.
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Neuroprotective effects of Theanine and its preventive effects on cognitive dysfunction.
Pharmacological research, 2011Co-Authors: Takami KakudaAbstract:Abstract Theanine (γ-glutamylethylamide) characteristically present in tea leaves (Camellia sinensis). It has a similar chemical structure to glutamate, which is a neurotransmitter related to memory. Theanine passes through the blood–brain barrier and has been shown to have a cerebroprotective effect and a preventive effect on neuronal cell death after transient cerebral ischemia. The neuroprotective effect is partly due to the antagonistic action of Theanine on glutamate receptor subtype AMPA and kainate receptors, but the affinity is very low. Theanine also acted on glutamine (Gln) transporter strongly and inhibited the incorporation of extracellular Gln into neurons, which in turn suppressed the conversion of Gln to glutamate by glutaminase, a reaction required for condensation into synaptic vesicles to form a neurotransmitter pool responsible for subsequent exocytotic release upon stimuli. In an investigation of elderly persons with normal or slight cognitive dysfunction, volunteers who ingested powdered green tea containing a high Theanine concentration (equivalent to 47.5 mg day−1 of Theanine) showed significantly lower decline in cognitive function compared with that of the placebo group. This result suggested that Theanine might have improved a slight cognitive dysfunction in elderly persons.
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Theanine, gamma-glutamylethylamide, is metabolized by renal phosphate-independent glutaminase.
Biochimica et biophysica acta, 2003Co-Authors: Haruhito Tsuge, Sachi Sano, Takashi Hayakawa, Takami Kakuda, Tomonori UnnoAbstract:The distribution of Theanine-degrading activity in Wistar rats was examined and this activity was detected only in the kidney. Judging from polyacrylamide gel electrophoresis, Theanine-degrading enzyme from rat kidney was purified almost to homogeneity. Theanine-degrading activity was co-purified with glutaminase activity, and the relative activity for Theanine was about 85% of that for L-glutamine throughout purification. Substrate specificity of purified enzyme preparation coincided well with the data of phosphate-independent glutaminase [EC 3.5.1.2], which had been previously reported. It was very curious that gamma-glutamyl methyl and ethyl esters were more effectively hydrolyzed than Theanine and L-glutamine, in view of relative activity and K(m) value. It was suggested that gamma-glutamyl moiety in Theanine molecule was transferred to form gamma-glutamylglycylglycine with relative ease in the presence of glycylglycine. On the other hand, purified phosphate-dependent glutaminase did not show Theanine-degrading activity at all. Thus, it was concluded that Theanine was hydrolyzed by phosphate-independent glutaminase in kidney and suggested that, as for the metabolic fate of Theanine, its glutamyl moiety might be transferred by means of gamma-glutamyl transpeptidase reaction to other peptides in vivo.
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Theanine, γ-glutamylethylamide, is metabolized by renal phosphate-independent glutaminase
Biochimica et Biophysica Acta, 2002Co-Authors: Haruhito Tsuge, Sachi Sano, Takashi Hayakawa, Takami Kakuda, Tomonori UnnoAbstract:Abstract The distribution of Theanine-degrading activity in Wistar rats was examined and this activity was detected only in the kidney. Judging from polyacrylamide gel electrophoresis, Theanine-degrading enzyme from rat kidney was purified almost to homogeneity. Theanine-degrading activity was co-purified with glutaminase activity, and the relative activity for Theanine was about 85% of that for l -glutamine throughout purification. Substrate specificity of purified enzyme preparation coincided well with the data of phosphate-independent glutaminase [EC 3.5.1.2], which had been previously reported. It was very curious that γ-glutamyl methyl and ethyl esters were more effectively hydrolyzed than Theanine and l -glutamine, in view of relative activity and K m value. It was suggested that γ-glutamyl moiety in Theanine molecule was transferred to form γ-glutamylglycylglycine with relative ease in the presence of glycylglycine. On the other hand, purified phosphate-dependent glutaminase did not show Theanine-degrading activity at all. Thus, it was concluded that Theanine was hydrolyzed by phosphate-independent glutaminase in kidney and suggested that, as for the metabolic fate of Theanine, its glutamyl moiety might be transferred by means of γ-glutamyl transpeptidase reaction to other peptides in vivo.
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Metabolism of Theanine, gamma-glutamylethylamide, in rats.
Journal of agricultural and food chemistry, 1999Co-Authors: Tomonori Unno, Takami Kakuda, Takashi Hayakawa, Yuko Suzuki, Haruhito TsugeAbstract:The metabolism of Theanine, one of the major amino acid components in tea (Camellia sinensis), was studied in rats. High-performance liquid chromatography (HPLC) with fluorometric detection was used to evaluate the nature of Theanine's metabolites in plasma, urine, and tissues. In the urine samples collected after administration of 100, 200, and 400 mg each of Theanine, intact Theanine, L-glutamic acid, and ethylamine, these compounds were detected in a dose-dependent manner. When 200 mg of Theanine was orally administered to rats, the plasma concentrations of Theanine and ethylamine reached their highest levels about 0.5 and 2 h after administration, respectively. It seems most likely that the enzymatic hydrolysis of Theanine to glutamic acid and ethylamine was accomplished in the kidney. These results indicate that orally administered Theanine is absorbed through the intestinal tract and hydrolyzed to glutamic acid and ethylamine in the rat kidney.
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reduction effect of Theanine on blood pressure and brain 5 hydroxyindoles in spontaneously hypertensive rats
Bioscience Biotechnology and Biochemistry, 1995Co-Authors: Hidehiko Yokogoshi, Takami Kakuda, Yukiko Kato, Yuko M Sagesaka, Takanobu Takiharamatsuura, Naokazu TakeuchiAbstract:The effect of Theanine, one of the components of green tea, on the blood pressure and brain 5-hydroxyindoles in spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY) was investigated by intraperitoneally administering Theanine. The effect of glutamine, which is structurally similar to Theanine, was also examined. When SHR were injected with various amounts of Theanine (0, 500, 1000, 1500, and 2000 mg/kg), the change was dose-dependent, and a significant decrease in blood pressure was observed with the high doses (1500 and 2000 mg/kg). A dose of 2000 mg/kg of Theanine did not alter the blood pressure of WKY, while the same dose to SHR decreased it significantly. On the other hand, glutamine administration to SHR did not change either the blood pressure or the heart rate. The brain 5-hydroxyindole level was significantly decreased by Theanine administration to both WKY and SHR, the decrease being dose-dependent.
Haruhito Tsuge - One of the best experts on this subject based on the ideXlab platform.
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Theanine, gamma-glutamylethylamide, is metabolized by renal phosphate-independent glutaminase.
Biochimica et biophysica acta, 2003Co-Authors: Haruhito Tsuge, Sachi Sano, Takashi Hayakawa, Takami Kakuda, Tomonori UnnoAbstract:The distribution of Theanine-degrading activity in Wistar rats was examined and this activity was detected only in the kidney. Judging from polyacrylamide gel electrophoresis, Theanine-degrading enzyme from rat kidney was purified almost to homogeneity. Theanine-degrading activity was co-purified with glutaminase activity, and the relative activity for Theanine was about 85% of that for L-glutamine throughout purification. Substrate specificity of purified enzyme preparation coincided well with the data of phosphate-independent glutaminase [EC 3.5.1.2], which had been previously reported. It was very curious that gamma-glutamyl methyl and ethyl esters were more effectively hydrolyzed than Theanine and L-glutamine, in view of relative activity and K(m) value. It was suggested that gamma-glutamyl moiety in Theanine molecule was transferred to form gamma-glutamylglycylglycine with relative ease in the presence of glycylglycine. On the other hand, purified phosphate-dependent glutaminase did not show Theanine-degrading activity at all. Thus, it was concluded that Theanine was hydrolyzed by phosphate-independent glutaminase in kidney and suggested that, as for the metabolic fate of Theanine, its glutamyl moiety might be transferred by means of gamma-glutamyl transpeptidase reaction to other peptides in vivo.
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Theanine, γ-glutamylethylamide, is metabolized by renal phosphate-independent glutaminase
Biochimica et Biophysica Acta, 2002Co-Authors: Haruhito Tsuge, Sachi Sano, Takashi Hayakawa, Takami Kakuda, Tomonori UnnoAbstract:Abstract The distribution of Theanine-degrading activity in Wistar rats was examined and this activity was detected only in the kidney. Judging from polyacrylamide gel electrophoresis, Theanine-degrading enzyme from rat kidney was purified almost to homogeneity. Theanine-degrading activity was co-purified with glutaminase activity, and the relative activity for Theanine was about 85% of that for l -glutamine throughout purification. Substrate specificity of purified enzyme preparation coincided well with the data of phosphate-independent glutaminase [EC 3.5.1.2], which had been previously reported. It was very curious that γ-glutamyl methyl and ethyl esters were more effectively hydrolyzed than Theanine and l -glutamine, in view of relative activity and K m value. It was suggested that γ-glutamyl moiety in Theanine molecule was transferred to form γ-glutamylglycylglycine with relative ease in the presence of glycylglycine. On the other hand, purified phosphate-dependent glutaminase did not show Theanine-degrading activity at all. Thus, it was concluded that Theanine was hydrolyzed by phosphate-independent glutaminase in kidney and suggested that, as for the metabolic fate of Theanine, its glutamyl moiety might be transferred by means of γ-glutamyl transpeptidase reaction to other peptides in vivo.
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Metabolism of Theanine, gamma-glutamylethylamide, in rats.
Journal of agricultural and food chemistry, 1999Co-Authors: Tomonori Unno, Takami Kakuda, Takashi Hayakawa, Yuko Suzuki, Haruhito TsugeAbstract:The metabolism of Theanine, one of the major amino acid components in tea (Camellia sinensis), was studied in rats. High-performance liquid chromatography (HPLC) with fluorometric detection was used to evaluate the nature of Theanine's metabolites in plasma, urine, and tissues. In the urine samples collected after administration of 100, 200, and 400 mg each of Theanine, intact Theanine, L-glutamic acid, and ethylamine, these compounds were detected in a dose-dependent manner. When 200 mg of Theanine was orally administered to rats, the plasma concentrations of Theanine and ethylamine reached their highest levels about 0.5 and 2 h after administration, respectively. It seems most likely that the enzymatic hydrolysis of Theanine to glutamic acid and ethylamine was accomplished in the kidney. These results indicate that orally administered Theanine is absorbed through the intestinal tract and hydrolyzed to glutamic acid and ethylamine in the rat kidney.
Zhengzhu Zhang - One of the best experts on this subject based on the ideXlab platform.
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Effect of shade treatment on Theanine biosynthesis in Camellia sinensis seedlings
Plant Growth Regulation, 2013Co-Authors: Weiwei Deng, Xiaochun Wan, Yue Fei, Shuo Wang, Zhengzhu ZhangAbstract:Theanine synthetase (TS) is a key enzyme involved in Theanine biosynthesis. In our recent study, it has been revealed that Theanine biosynthesis derived from nitrogen metabolism in tea (Camellia sinensis) plants can be influenced by shading treatment. The expression patterns of CsTS protein in the roots and shoots of tea seedlings were examined by western blot using a self-prepared polyclonal antibody with high specificity and sensitivity. The effect of long-term shade treatment on the levels of Theanine synthesis was also investigated using roots and shoots of tea seedlings. Levels of Theanine and total free amino acids gradually increased in shoots, reaching their maximum after 22 days of treatment (DOT). The immunoblotting analysis suggested that CsTS protein levels increased gradually up to 22 DOT and expression remained at a high level, except after 1 DOT where levels were low in both roots and shoots. The increased Theanine concentration we observed in the shading treatment may be due to increased nitrogen assimilation and reduced Theanine catabolism under shade conditions.
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Effect of salt treatment on Theanine biosynthesis in Camellia sinensis seedlings
Plant physiology and biochemistry : PPB, 2012Co-Authors: Weiwei Deng, Qi Chen, Shuo Wang, Zhengzhu ZhangAbstract:Theanine synthetase (TS) is a key enzyme involved in Theanine biosynthesis. In our recent study, it has been revealed that Theanine biosynthesis derived from nitrogen metabolism in tea (Camellia sinensis) plants can be influenced by shading treatment. The expression patterns of CsTS protein in the roots and shoots of tea seedlings were examined by western blot using a self-prepared polyclonal antibody with high specificity and sensitivity. The effect of long-term shade treatment on the levels of Theanine synthesis was also investigated using roots and shoots of tea seedlings. Levels of Theanine and total free amino acids gradually increased in shoots, reaching their maximum after 22 days of treatment (DOT). The immunoblotting analysis suggested that CsTS protein levels increased gradually up to 22 DOT and expression remained at a high level, except after 1 DOT where levels were low in both roots and shoots. The increased Theanine concentration we observed in the shading treatment may be due to increased nitrogen assimilation and reduced Theanine catabolism under shade conditions.
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intestinal transport of pure Theanine and Theanine in green tea extract green tea components inhibit Theanine absorption and promote Theanine excretion
Food Chemistry, 2011Co-Authors: Jinsong Zhang, Xiaochun Wan, Men Long, Pandeng Lei, Zhengzhu ZhangAbstract:Abstract Theanine, an amino acid contained in green tea, is known to possess many pharmacological functions. In this paper, we investigated the absorption of Theanine in the human intestinal epithelium, using a Caco-2 monolayer model. Different concentrations of either pure Theanine or green tea extracts were administered to Caco-2 cells. The Theanine content in the samples was analysed by high-performance liquid chromatography, coupled with fluorescence detection. Cell permeation was also measured. The data revealed that the transport of pure Theanine occurred in a manner consistent with passive diffusion. Surprisingly, pure Theanine showed good absorption, whereas Theanine in the green tea extract was poorly absorbed in the Caco-2 cell model. Furthermore, the transport of Theanine in green tea extract in the basolateral (BL) to apical (AP) direction was much greater than that in the AP–BL direction, suggesting that green tea components profoundly affect the trans-epithelial transport of Theanine in this Caco-2 cell model.
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Chemical Synthesis and the Stability of Theanine
Advanced Materials Research, 2011Co-Authors: Zhengzhu Zhang, Shou He Yan, Da Xiang Li, Tie Jun Ling, Marc Meurens, Yvan LarondelleAbstract:A chemical synthesis procedure for Theanine from L-pyrrolidonecarboxylic acid (L-PCA) and ethylamine was modified. L-PCA was allowed to react with excess anhydrous ethylamine (>99%) to produce Theanine at 35°C for 10 days. The Theanine crystallized from 84% ethanol (V/V) at 4°C with yield of 17-30%. Results shown that L-PCA was conversed into Theanine and a 98.2% yield of Theanine was obtained by freeze-drying of the reacted mixture directly after reaction in the same manner. The synthesized products were identified by 1H-NMR and MS analysis. Both the isomers existed in products while the L-Theanine was dominant. When 10% L-PCA aqueous solution was kept at 4°C for 60 days, about 13% L-PCA decomposed to yield glutamic acid. Since the aqueous solution of ethylamine is a kind of strong base, which may result in decomposed of L-PCA and L-Theanine to form glutamic acid. Therefore, the anhydrous ethylamine was used as the substrate. The optimal conditions for Theanine crystallization were also discussed.
Takashi Hayakawa - One of the best experts on this subject based on the ideXlab platform.
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Theanine, gamma-glutamylethylamide, is metabolized by renal phosphate-independent glutaminase.
Biochimica et biophysica acta, 2003Co-Authors: Haruhito Tsuge, Sachi Sano, Takashi Hayakawa, Takami Kakuda, Tomonori UnnoAbstract:The distribution of Theanine-degrading activity in Wistar rats was examined and this activity was detected only in the kidney. Judging from polyacrylamide gel electrophoresis, Theanine-degrading enzyme from rat kidney was purified almost to homogeneity. Theanine-degrading activity was co-purified with glutaminase activity, and the relative activity for Theanine was about 85% of that for L-glutamine throughout purification. Substrate specificity of purified enzyme preparation coincided well with the data of phosphate-independent glutaminase [EC 3.5.1.2], which had been previously reported. It was very curious that gamma-glutamyl methyl and ethyl esters were more effectively hydrolyzed than Theanine and L-glutamine, in view of relative activity and K(m) value. It was suggested that gamma-glutamyl moiety in Theanine molecule was transferred to form gamma-glutamylglycylglycine with relative ease in the presence of glycylglycine. On the other hand, purified phosphate-dependent glutaminase did not show Theanine-degrading activity at all. Thus, it was concluded that Theanine was hydrolyzed by phosphate-independent glutaminase in kidney and suggested that, as for the metabolic fate of Theanine, its glutamyl moiety might be transferred by means of gamma-glutamyl transpeptidase reaction to other peptides in vivo.
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Theanine, γ-glutamylethylamide, is metabolized by renal phosphate-independent glutaminase
Biochimica et Biophysica Acta, 2002Co-Authors: Haruhito Tsuge, Sachi Sano, Takashi Hayakawa, Takami Kakuda, Tomonori UnnoAbstract:Abstract The distribution of Theanine-degrading activity in Wistar rats was examined and this activity was detected only in the kidney. Judging from polyacrylamide gel electrophoresis, Theanine-degrading enzyme from rat kidney was purified almost to homogeneity. Theanine-degrading activity was co-purified with glutaminase activity, and the relative activity for Theanine was about 85% of that for l -glutamine throughout purification. Substrate specificity of purified enzyme preparation coincided well with the data of phosphate-independent glutaminase [EC 3.5.1.2], which had been previously reported. It was very curious that γ-glutamyl methyl and ethyl esters were more effectively hydrolyzed than Theanine and l -glutamine, in view of relative activity and K m value. It was suggested that γ-glutamyl moiety in Theanine molecule was transferred to form γ-glutamylglycylglycine with relative ease in the presence of glycylglycine. On the other hand, purified phosphate-dependent glutaminase did not show Theanine-degrading activity at all. Thus, it was concluded that Theanine was hydrolyzed by phosphate-independent glutaminase in kidney and suggested that, as for the metabolic fate of Theanine, its glutamyl moiety might be transferred by means of γ-glutamyl transpeptidase reaction to other peptides in vivo.
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Metabolism of Theanine, gamma-glutamylethylamide, in rats.
Journal of agricultural and food chemistry, 1999Co-Authors: Tomonori Unno, Takami Kakuda, Takashi Hayakawa, Yuko Suzuki, Haruhito TsugeAbstract:The metabolism of Theanine, one of the major amino acid components in tea (Camellia sinensis), was studied in rats. High-performance liquid chromatography (HPLC) with fluorometric detection was used to evaluate the nature of Theanine's metabolites in plasma, urine, and tissues. In the urine samples collected after administration of 100, 200, and 400 mg each of Theanine, intact Theanine, L-glutamic acid, and ethylamine, these compounds were detected in a dose-dependent manner. When 200 mg of Theanine was orally administered to rats, the plasma concentrations of Theanine and ethylamine reached their highest levels about 0.5 and 2 h after administration, respectively. It seems most likely that the enzymatic hydrolysis of Theanine to glutamic acid and ethylamine was accomplished in the kidney. These results indicate that orally administered Theanine is absorbed through the intestinal tract and hydrolyzed to glutamic acid and ethylamine in the rat kidney.
