Practical Protein Chemistry - A. Darbre 1989

Application of electron impact mass spectrometry for determining the amino acid sequence of peptides and proteins
Special cases of method application
Proteins containing γ-carboxyglutamic acid residues

The mass spectrometry method allows for the unambiguous identification of $\gamma$-carboxyglutamic acid residues in a peptide chain [9, 29]. To achieve this, Peptides are acetylated and permethylated using standard Procedures (Sections 19.4.4 and 19.4.5), and the modified mixture is analyzed by mass spectrometry. The presence of an N-terminal $\gamma$-carboxyglutamic acid residue in the peptide is indicated by the appearance of ion peaks 3 and 4 at $m/z$ 112 and 170 in its mass spectrum. The presence of ion peaks 5 and 6 at $m/z$ 171 and 229 Da in the spectra indicates the presence of a $\gamma$-carboxyglutamic acid residue within the peptide chain.

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Last update: 06/08/2026

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