Fast- and slow-reacting, protonated, Z-blocked (Z = benzyloxycarbonyl) phenylalanylphenylalanine and alanylphenylalanyl diasteromeric dipeptides undergo decarboxylation through two competing pathways assisted by the migration of the urethane benzyl group either to the terminal or to the amidic nitrogens. The reaction mechanism has been proved by tandem mass spectrometric experiments. The different kinetic energy released associated with CO2 elimination allows the distinction of the S,S from the R,S isomers by mass-analysed ion kinetic-energy experiments.
CHARACTERIZATION OF Z-BLOCKED ISOMERIC DIPEPTIDES BY FAST-ATOM-BOMBARDMENT TANDEM MASS-SPECTROMETRY AND KINETIC-ENERGY RELEASE MEASUREMENTS
SINDONA, Giovanni;
1992-01-01
Abstract
Fast- and slow-reacting, protonated, Z-blocked (Z = benzyloxycarbonyl) phenylalanylphenylalanine and alanylphenylalanyl diasteromeric dipeptides undergo decarboxylation through two competing pathways assisted by the migration of the urethane benzyl group either to the terminal or to the amidic nitrogens. The reaction mechanism has been proved by tandem mass spectrometric experiments. The different kinetic energy released associated with CO2 elimination allows the distinction of the S,S from the R,S isomers by mass-analysed ion kinetic-energy experiments.File in questo prodotto:
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