Theanine Formation by Tea Suspension Cells.

The theanine (THE: gamma-glutamylethylamide) content and the growth rate of cultured cells of tea (Camellia sinensis L.) were increased greatly to 22.3% in dry wt. with a medium containing 60 mM nitrate and 25 mM ethylamine as a nitrogen source. The optimum concentrations of nitrate, Mg2+, and K+ for the growth and formation of THE in suspension cells were 40 mM, 3 mM, and 104 mM, respectively. The yield of THE accumulated in the cultured cells with the medium modified for THE formation was increased greatly due to a great increase of the growth rate.