Synthesis of Deuterium, Tritium and 14-Carbon Labelled Isotopomers of L-DOPA

The synthesis of five isotopomers ofL-DOPA labelled selectively with deuterium, tritium and 14 C is reported. The isotopomers of L-tyrosine, the intermediate substrates for this synthesis, were obtained using chemical and enzymatic methods. Selectively labelled isotopomers of L-tyrosine were hydroxylated respectively to [3R- 3 H]-L, [5'- 2 H]-L, [2',6'- 2 H 2 ]-L, doubly labelled [5'- 2 H/ 3 H]-L, and [1- 14 C]-L-DOPA using activity of enzyme tyrosine (EC 1.14.18.1) isolated from mushrooms.