Synthesis of [3-14C]-L-tryptophan and 5′-hydroxy-[3-14C]-L-tryptophan

Abstract

The synthesis of selectively labeled [3-14C]-L-tryptophan and its derivative 5′-hydroxy-[3-14C]-L-tryptophan using chemical and multienzymatic methods is reported. The key intermediate for this synthesis, [3-14C]-DL-alanine was obtained from 14CH3I as a result of its condensation with N-(diphenylmethylene)glycine tert-butyl ester. Next, the mixture containing [3-14C]-DL-alanine, indole or 5-hydroxyindole has been converted to [3-14C]-L-tryptophan or 5′-hydroxy-[3-14C]-L-tryptophan, respectively, in a one-pot multienzymatic reaction using four enzymes: D-amino acid oxidase, catalase, glutamic-pyruvic transaminase and tryptophanase.