The use of hydrogen-deuterium exchange to facilitate peptide sequencing by electrospray tandem mass spectrometry

The utility of hydrogen‐deuterium exchange for sequencing peptides by mass spectrometry is demonstrated. The number of exchangeable hydrogens in a peptide is readily obtained by electrospray analysis of the peptide dissolved in deuterated solvents. This information can be used, in conjunction with published computer algorithms for interpreting peptide mass spectra, to reduce significantly the number of candidate sequences that fit the experimentsl data. This information, when combined with fragment‐ion information in the mass spectrum, greatly increases the reliability of sequence determination.