Enzymatic synthesis of tryptamine and its halogen derivatives selectively labeled with hydrogen isotopes.

Nine isotopomers of tryptamine and its halogen derivatives, labeled with deuterium, tritium in side chain, i.e., [()-H]-, [()-H]-, 5-F-[()-H]-, 5-F-[()-H]-, 5-Br-[()-H]-, double labeled [()-H/H]-, 5-F-[()-H/H]-, and ring labeled [4-H]-, and [5-H]-tryptamine, were obtained by enzymatic decarboxylation of l-Trp and its appropriate derivatives in deuteriated or tritiated media, respectively. Intermediates: [5'-H]-l-Trp used for further decarboxylation was synthesized by enzymatic coupling of [5-H]-indole with -methyl-l-cysteine, and [4'-H]-l-Trp was obtained by isotope exchange H/H of the authentic l-Trp dissolved in heavy water induced by UV-irradiation. Doubly labeled [()-H/H]- and 5-F-[()-H/H]-tryptamine were obtain by decarboxylation of l-Trp or [5'-F]-l-Trp carried out in HHO incubation medium.