Quantitative protein sequencing using mass spectrometry: thermally induced formation of thiohydantoin amino acid derivatives from N-methyl- and N-phenylthiourea amino acids and peptides in the mass spectrometer

✍ Scribed by T. Fairwell; S. Ellis; R.E. Lovins

• Publisher: Elsevier Science
• Year: 1973
• Tongue: English
• Weight: 365 KB
• Volume: 53
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(73)90412-0

✦ Synopsis

The thermally induced formation of methyl-and phenylthiohydantoin amino acid derivatives from the corresponding N-methyl-and N-phenylthiourea derivatives of amino acids and peptides has been shown to occur in the mass spectrometer. A comparison of the mass spectra of a number of amino acid thiourea derivatives with those of the corresponding thiohydantoin derivatives has been made and the apparent similarities have been noted. The similarity in mass spectral behavior suggests that the thiourea derivative undergoes a thermal rearrangement during mass spectral analysis to the thiohydantoin which is subsequently ionized and detected. Support for this suggestion is found in the mass spectral behavior of N-terminal thiourea peptides derivatives which are shown to also rearrange in the mass spectrometer to produce the thiohydantoin of the N-terminal amino acid which is ionized and detected. The utility of the resulting analytical procedure for amino acid analysis and end group analysis is discussed.