Specific features of deuterium and tritium labeling of Pro-Gly-Pro-Leu and of physiologically active amino acids

Abstract

γ-Aminobutyric acid (GABA), 3-hydroxy-L-tyrosine (D0PA), and Pro-Gly-Pro-Leu were labeled with hydrogen isotopes. The mean deuterium content per molecule was 7.5 atoms in Pro-Gly-Pro-Leu and up to 4 atoms in GABA and DOPA. The incorporation of isotopes depending on the reaction conditions was monitored by mass spectrometry. The isotope exchange efficiency was found to strongly depend not only on the reaction temperature and catalyst: substrate ratio, but also on processes occurring on the support surface.