Synthesis of isotopomers of <Emphasis Type="SmallCaps">l</Emphasis>-DOPA and dopamine labeled with hydrogen isotopes in the side chain

The enzymatic synthesis of three isotopomers of l-DOPA labeled with deuterium and tritium at α carbon atom was elaborated. These compounds were converted into (1S)-²H]–, (1S)- ³H]–, and doubly labeled (1S)-²H/³H]-dopamines using enzyme tyrosine decarboxylase. Doubly labeled (1R) isotopologue, i.e., (1R)-²H/³H]-dopamine, was afforded by enzymatic decarboxylation of authentic l-DOPA carried out in deuteriated and tritiated incubation medium.