Deuterated peptides: Platinum catalyzed exchange labeling of leucine enkephalin and related peptides

Platinum catalyzed hydrogen-deuterium exchange labeling of phenylalanine and tyrosine containing peptides in deuterium oxide is exemplified by the preparation of deuterium labeled leucine enkephalin and related peptides. NMR and mass spectral evidence indicates that the side chains of the aromatic residues are the sites of label incorporation. Time course studies with N-acetyltyrosine and tyrosyl-glycine suggest that the exchange of the aromatic protons occurs most rapidly followed by exchange of the benzylic protons adjacent to the aromatic ring.