Enzymatic synthesis of halogen derivatives of L‐phenylalanine and phenylpyruvic acid stereoselectively labeled with hydrogen isotopes in the side chain

Halogenated, labeled with deuterium, tritium or doubly labeled with deuterium and tritium in the 3S position of the side chain isotopomers of L‐phenylalanine and phenylpyruvic acid were synthesized. Isotopomers of halogenated L‐phenylalanine were obtained by addition of ammonia from isotopically enriched buffer solution to the halogenated derivative of (E)‐cinnamic acid catalyzed by phenylalanine ammonia lyase. Isotopomers of halogenated phenylpyruvic acid were obtained enzymatically by conversion of the appropriate isotopomer of halogenated L‐phenylalanine in the presence of phenylalanine dehydrogenase. As a source of deuterium was used deuterated water, as a source of tritium was used a solution of highly diluted tritiated water. The labeling takes place in good yields and with high deuterium atom% abundance.