Theanine (γ-glutamyl-L-ethylamide) is the most abundant non-protein amino acid in tea leaves. In addition to Camellia sinensis, theanine occurs in several plants belonging to the Ericales. Biosynthesis of theanine from glutamic acid and ethylamine by theanine synthetase is present in all organs of tea seedlings, but roots are the major site of theanine biosynthesis in adult tea trees. Theanine is transported from roots to young leaves via the xylem sap. Theanine is hydrolysed to glutamic acid and ethylamine in leaves. Ethylamine produced from theanine is predominantly used for catechin biosynthesis. Concentration of ammonia and light intensity influence the biosynthesis and degradation of theanine, respectively. Biosynthesis, translocation and degradation of theanine and related enzymes and genes are reviewed.
SakatoY. (1949) The chemical constituents of tea: III. A new amide theanine. Nippon Nogeikagaku Kaishi, Japan, 23, 262-267.
2.
NakagawaM. (2009) The History of Tea, Kyorin, Tokyo.
3.
KonishiS, TakahashiE. (1966) Existence and synthesis of L-glutamic acid γ-methylamide in tea plants. Plant and Cell Physiology, 7, 171-175.
4.
YamaguchiS, NinomiyaK. (2000) Umami and food palatability. The Journal of Nutrition, 130, 921S-926S.
5.
ChuD, KobayashiK, JunejaLRYamamotoT. (1997) Theanine - its synthesis, isolation, and physiological activity. In Chemistry and Applications of Green Tea, YamamotoT, JunejaLRChuD, KimM. (Eds), CRC Press, Boca Raton, 129-135.
6.
WanX, ZhangZ, LiD. (2009) Chemistry and biological properties of theanine. In Tea and Tea Products, CRC Press, 255-274.
7.
VuongQVBowyerMCRoachPD. (2011) L-Theanine: Properties, synthesis and isolation from tea. Journal of the Science of Food and Agriculture, 91, 1931-1939.
8.
KonishiS, MatsudaT, TakahashiE. (1969) Comparative studies on the synthesis of theanine and L-glutamic acid γ-methylamide in Thea sinensis, Camellia sasanqua, and Oryza sativa. Nippon Dojouhiryougaku Zassi40, 107-112.
9.
NagataT, SakaiS. (1984) Differences in caffeine, flavonols and amino acids contents in leaves of cultivated species of Camellia. Japanese Journal of Breeding, 34, 459-467.
10.
TsushidaT, TakeoT. (1984) Occurrence of theanine in Camellia japonica and Camellia sasanqua seedlings. Agricultural and Biological Chemistry, 48, 2861-2862.
11.
NagataT, SakaiS. (1985) Caffeine, flavanol and amino acid contents in leaves of hybrids and species of the section Dubiae in the genus Camellia. Japanese Journal of Breeding, 35, 1-8.
12.
NagataT. (1986) Differences in caffeine, flavanols and amino acids contents in leaves of cultivated species and hybrids in the genus Camellia. Japan Agricultural Research Quarterly, 19, 276-280.
13.
DengW-W, OgitaS, AshiharaH. (2010) Distribution and biosynthesis of theanine in Theaceae plants. Plant Physiology and Biochemistry, 48, 70-72.
14.
SuzukiM. (2013) Chemistry of tea. In Function and Science of Tea, MoritaA, MasudaS, NakamuraN, SumikawaO, SuzukiM. (Eds), Asakura-Shoten, Tokyo, 98-108.
15.
FeldheimW, YongvanitP, CummingsPH. (1986) Investigation of the presence and significance of theanine in the tea plant. Journal of the Science of Food and Agriculture, 37, 527-534.
16.
FuruyaT, OriharaY, TsudaY. (1990) Caffeine and theanine from cultured cells of Camellia sinensis. Phytochemistry, 29, 2539-2543.
17.
OriharaY, FuruyaT. (1990) Production of theanine and other γ-glutamyl derivatives by Camellia sinensis cultured cells. Plant Cell Reports, 9, 65-68.
18.
MatsuuraT, KakudaT. (1990) Effects of precursor, temperature, and illumination on theanine accumulation in tea callus. Agricultural and Biological Chemistry, 54, 2283-2286.
19.
MatsuuraT, KakudaT, KinoshitaT, TakeuchiN, SasakiK. (1992) Theanine formation by tea suspension cells. Bioscience, Biotechnology, and Biochemistry, 56, 1179-1181.
20.
Takihara-MatsuuraT, SakaneI, KakudaT, KitadaT, KinoshitaT, TakeuchiN. (1994) Effects of plant growth regulators and carbon sources on theanine formation in callus cultures of tea (Camellia sinensis). Bioscience, Biotechnology, and Biochemistry, 58, 1519-1521.
21.
CasimirJ, JadotJ, RenardM. (1960) Separation and characterization of N-ethyl-γ-glutamine from Xerocomus badius. Biochimica et Biophysica Acta, 39, 462-468.
22.
SasaokaK, KitoM, KonishiS, InagakiH. (1962) Studies on the biosynthesis of theanine in tea seedlings: Incorporation of glutamic-1-14C into theanine. Agricultral and Biological Chemistry, 26, 265-266.
23.
KitoM, KokuraH, IzakiJ, SasaokaK. (1966) Fate of the radioactive carbon of theanine labeled with ethylamine-1-14C in tea seedlings. Agricultural and Biological Chemistry, 30, 623-624.
24.
DengW-W, OgitaS, AshiharaH. (2008) Biosynthesis of theanine (γ-ethylamino-L-glutamic acid) in seedlings of Camellia sinensis. Phytochemistry Letters, 1, 115-119.
25.
SasaokaK, KitoM, InagakiH. (1963) Studies on the biosynthesis of theanine in tea seedlings: Synthesis of theanine by the homogenate of tea. Agricultural and Biological Chemistry, 27, 467-468.
26.
CrocomoOJFowdenL. (1970) Amino acid decarboxylases of higher plants: The formation of ethylamine. Phytochemistry, 9, 537-540.
27.
SteinerM, HartmannT, DöngesD, BastE. (1967) Biosynthese flüchtiger Amine durch eine Amin-Transaminase in Blütenpflanzen. Naturwissenschaften, 54, 370-371.
28.
TakeoT. (1974) L-Alanine as a precursor of ethylamine in Camellia sinensis. Phytochemistry, 13, 1401-1406.
29.
TakeoT. (1978) L-alanine decarboxylase in Camellia sinensis. Phytochemistry, 17, 313-314.
30.
DengW-W, OgitaS, AshiharaH. (2009) Ethylamine content and theanine biosynthesis in different organs of Camellia sinensis seedlings. Zeitschrift für Naturforschung64c, 387–390 (Erratum: 64c, 906).
31.
SasaokaK, KitoM, OnishiY. (1964) Synthesis of theanine by pea seed acetone powder extract. Agricultural and Biological Chemistry, 28, 318-324.
32.
SasaokaK, KitoM, OnishiY. (1965) Some properties of the theanine synthesizing enzyme in tea seedlings. Agricultural and Biological Chemistry, 29, 984-988.
33.
LiP, WanXCZhangZZLiJ, ShenZJ. (2005) A novel assay method for theanine synthetase activity by capillary electrophoresis. Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences, 819, 81-84.
34.
OkadaY, OzekiM, ShuM, AoiN, AbeI. (2006) Theanine synthetase. In Japan Patent, JP 2006–254780A, Japan.
35.
WuH, ChenD, LiJ, YuB, QiaoX, HuangH, HeY. (2013) De novo characterization of leaf transcriptome using 454 sequencing and development of EST-SSR markers in tea (Camellia sinensis). Plant Molecular Biology Reporter, 31, 524-538.
36.
MoritaA, OhtaM, YoneyamaT. (1998) Uptake, transport and assimilation of 15N-nitrate and 15N-ammonium in tea (Camellia sinensis L.)plants. Soil Science and Plant Nutrition, 44, 647-654.
37.
RuanJ, GerendasJ, HardterR, SattelmacherB. (2007) Effect of root zone pH and form and concentration of nitrogen on accumulation of quality-related components in green tea. Journal of the Science of Food and Agriculture, 87, 1505-1516.
38.
YangYYLiXHRatcliffeRGRuanJY. (2013) Characterization of ammonium and nitrate uptake and assimilation in roots of tea plants. Russian Journal of Plant Physiology, 60, 91-99.
39.
KonishiS. (1991) Plant nutrition of tea trees. In Tea Science, MuramatsuK. (Ed), Asakura Shoten, Tokyo, 21-32.
40.
IshigakiK. (1978) Studies on the nutritive characteristics of tea plant. Bulletin of the National Research Institute of Tea, 14, 1-152.
41.
HayatsuM, KosugeN. (1993) Autotrophic nitrification in acid tea soils. Soil Science and Plant Nutrition, 39, 209-217.
42.
OkanoK, ChutaniK, MatsuoK. (1997) Suitable level of nitrogen fertilizer for tea (Camellia sinensis L. plants in relation to growth, photosynthesis, nitrogen uptake and accumulation of free amino acids. Japanese Journal of Crop Science, 66, 279-287.
43.
CoruzziG, LastR. (2000) Amino acids. In Biochemistry and Molecular Biology of Plants, BuchananBBGruissemW, JonesRL. (Eds), American Society of Plant Physiologists, Rockville, 358-410.
44.
VenkatesanS. (2005) Impact of genotype and micronutrient applications on nitrate reductase activity of tea leaves. Journal of the Science of Food and Agriculture, 85, 513-516.
45.
VenkatesanS, GanapathyMnk. (2004) Nitrate reductase activity in tea as influenced by various levels of nitrogen and potassium fertilizers. Communications in Soil Science and Plant Analysis, 35, 1283-1291.
46.
RanaN, MohanpuriaP, YadavS. (2008) Cloning and characterization of a cytosolic glutamine synthetase from Camellia sinensis (L.) O. Kuntze that is upregulated by ABA, SA, and H2O2. Molecular Biotechnology, 39, 49-56.
47.
RanaNKMohanpuriaP, YadavSK. (2008) Expression of tea cytosolic glutamine synthetase is tissue specific and induced by cadmium and salt stress. Biologia Plantarum, 52, 361-364.
48.
MiflinBJLeaPJ. (1976) The pathway of nitrogen assimilation in plants. Phytochemistry, 15, 873-885.
49.
TakeoT. (1980) Ammonium-type nitrogen assimilation in tea plants. Agricultural and Biological Chemistry, 44, 2007-2012.
50.
TakeoT. (1979) Glutamate dehydrogenase from tea rootlet. Agricultural and Biological Chemistry, 43, 2257-2263.
51.
IbarashlI, SadonT, MorH. (1973) Induction of a specific isoenzyme of glutamate dehydrogenase by ammonia in oat leaves. Nature New Biology, 244, 150-152.
52.
KonishiS, KasaiZ. (1968) Synthesis of theanine from 14CO2 in tea plants and sites of the synthesis. Nippon Dojouhiryougaku Zasshi, 39, 439-443.
53.
KonishiS, TakahashiE. (1969) Metabolism of 14C labeled theanine. [N-ethyl-14C]theanine and its metabolic redistribution in the tea plant. Nippon Dojouhiryougaku Zasshi, 40, 479-484.
54.
OhK, KatoT, XuHL. (2008) Transport of nitrogen assimilation in xylem vessels of green tea plants fed with NH4-N and NO3-N. Pedosphere, 18, 222-226.
55.
BowsherC, SteerM, TobinA. (2012) Plant Biochemistry, Garland Science, New York.
56.
TsushidaT, TakeoT. (1985) An enzyme hydrolyzing L-theanine in tea leaves. Agricultural and Biological Chemistry, 49, 2913-2917.
57.
KitoM, KokuraH, IzakiJ, SasaokaK. (1966) Fate of the radioactive carbon of theanine labeled with ethylamine-L-14C in tea seedlings. Agricultural and Biological Chemistry, 30, 623-624.
58.
KitoM, KokuraH, IzakiJ, SasaokaK. (1968) Theanine, a precursor of the phloroglucinol nucleus of catechins in tea plants. Phytochemistry, 7, 599-603.
59.
KonishiS, InoueT, TakahashiE. (1972) Localization of the carbon in caffeine biosynthesized from N-methyl carbon of γ-glutamylmethylamide in tea plants. Plant and Cell Physiology, 13, 695-702.
60.
AshiharaH, SanoH, CrozierA. (2008) Caffeine and related purine alkaloids: Biosynthesis, catabolism, function and genetic engineering. Phytochemistry, 69, 841-856.
61.
ZhangQ, ShiY, MaL, YiX, RuanJ. (2014) Metabolomic analysis using ultra-performance liquid chromatography-quadrupole-time of flight mass spectrometry (UPLC-Q-TOF MS) uncovers the effects of light intensity and temperature under shading treatments on the metabolites in tea. PLoS ONE, 9, e112572.
62.
YangZ, KobayashiE, KatsunoT, AsanumaT, FujimoriT, IshikawaT, TomomuraM, MochizukiK, WataseT, NakamuraY, WatanabeN. (2012) Characterisation of volatile and non-volatile metabolites in etiolated leaves of tea (Camellia sinensis) plants in the dark. Food Chemistry, 135, 2268-2276.
63.
DengW-W, FeiY, WangS, WanX-C, ZhangZ-Z, HuX-Y. (2013) Effect of shade treatment on theanine biosynthesis in Camellia sinensis seedlings. Plant Growth Regulation, 71, 295-299.
64.
FengL, GaoM-J, HouR-Y, HuX-Y, ZhangL, WanX-C, WeiS. (2014) Determination of quality constituents in the young leaves of albino tea cultivars. Food Chemistry, 155, 98-104.
65.
DengW-W, WangS, ChenQ, ZhangZ-Z, HuX-Y. (2012) Effect of salt treatment on theanine biosynthesis in Camellia sinensis seedlings. Plant Physiology and Biochemistry, 56, 35-40.
66.
GivanCV. (1979) Metabolic detoxification of ammonia in tissues of higher plants. Phytochemistry, 18, 375-382.
67.
HachiyaT, WatanabeCKFujimotoM, IshikawaT, TakaharaK, Kawai-YamadaM, UchimiyaH, UesonoY, TerashimaI, NoguchiK. (2012) Nitrate addition alleviates ammonium toxicity without lessening ammonium accumulation, organic acid depletion and inorganic cation depletion in Arabidopsis thaliana shoots. Plant and Cell Physiology, 53, 577-591.
68.
KonishiS, YamajiR. (1982) Metabolism of theanine, glutamine, and asparagine in tea shoots. Nippon Dojouhiryougaku Zasshi, 53, 241-246.
69.
BindalS, GuptaR. (2014) L-Theanine synthesis using γ-glutamyl transpeptidase from Bacillus licheniformis ER-15. Journal of Agricultural and Food Chemistry, 62, 9151-9159.
70.
KamiyaS, SatakeK. (2010) Nitrate pollution and acidification in the area of tea garden. Chikyu Kankyou, 15, 161–170.
