反应详情

A reaction solution (100 ml) containing 100 mM potassium phosphate buffer (pH 6.5), 1 U of N-acylamino acid racemase, 1 U of L-aminoacylase (Sigma Co.), and 15% N-acetyl-DL-tryptophan was incubated at 30° C. overnight. As the reaction progressed, L-tryptophan produced was saturated in the aqueous phase and precipitated upon oversaturation in the aqueous phase, during which process the reaction was continued. The L-tryptophan precipitated in the aqueous phase was separated by filtration, washed with water, and dried (70% recovery). The optical purity of L-tryptophan thus produced was determined as follows. CHIRALPAK WH (DAICEL CHEMICAL INDUSTRIES, LTD.) was used to measure the purity at room temperature using 0.25 mM cupric sulfate as eluent (flow rate, 1 ml/min; detection wavelength, 254 nm). As a result, L-tryptophan with the optical purity of nearly 100% ee was obtained by the method of the present invention.