Synthesis of l-Tryptophan from Pyruvate,Ammonia and Indole

The tryptophanase activity which synthesizes l-tryptophan from pyruvate, ammonia and indole, was found to be widely distributed in cells of bacteria belonging to Enterobacteriaceae, such genera as Escherichia, Kluyvera, Enterobacter, Erwinia and Proteus. With the cells of Proteus rettgeri, equilibrium of the elimination reaction of l-tryptophan in the presence of high concentration of ammonia was studied. It was found that the equilibrium inclines toward the synthetic state.

When 5-hydroxy- and 5-methyl-indole were substituted for indole, 5-hydroxy- and 5-methyl-l-tryptophan, respectively, were synthesized. The synthesis of l-tryptophan was also observed with indole and various amino acids, S-methyl-l-cysteine, S-ethyl-l-cysteine, l-cysteine, 5-fluoro-dl-tryptophan, or oxalacetic acid.