6.3.1.6	metabolism	the enzyme is involved in theanine biosynthesis in tea plants. Theanine is the most abundant amino acid in tea seedlings	728499	
6.3.1.6	metabolism	theanine synthetase is a key enzyme involved in theanine biosynthesis, theanine biosynthesis is derived from nitrogen metabolism in Camellia sinensis	728477	
6.3.1.6	physiological function	the flavor of tea is conferred by certain metabolites, especially L-theanine, in Camellia sinensis. More L-theanine accumulates in Camellia sinensis than in other plants. L-Glutamic acid, a precursor of L-theanine, is present in most plants, while ethylamine, another precursor of L-theanine, specifically accumulates in Camellia species, especially Camellia sinensis. Most plants contain the enzyme/gene, glutamate-ethylamine ligase, catalyzing the conversion of ethylamine and L-glutamic acid to L-theanine. After supplementation with [2H5]ethylamine, all the plants tested (Camellia nitidissima, Camellia japonica, Zea mays, Arabidopsis thaliana, and Solanum lycopersicum) produce [2H5]l-theanine, which suggests that ethylamine availability is the reason for the difference in L-theanine accumulation between Camellia sinensis and other plants	745146