Synthesis of three isotopomers of L-tryptophan via a combination of organic synthesis and biotechnology

Article abstract of DOI:10.1002/recl.19881070206

In this paper, we report the preparation of three isotopomers of L-tryptophan on a gram scale, specifically labelled with 99percent 15N (position 1) and 99percent 13C (position 2) in the indole ring; for position 3, the incorporation was 90percent 13C.The isotopically enriched indoles were synthesized from H(15)NO3, K(13)CN and (13)CH3CN and then converted, with L-serine, into the corresponding labelled L-tryptophans using genetic manipulated E. coli bacteria, which contain high amounts of the enzyme tryptophan synthetase.The 13C-13C, 13C-1H, 13C-15N and 15N-1H coupling constants of the indoles and the tryptophans were determined from the 1H NMR and 13C NMR spectra.