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 application of the method
Peptides with a blocked N-terminal amino group

The Amino Acid Sequence of Peptides lacking a free $\alpha$-amino group cannot be determined by classical Methods, but it is readily established by mass spectrometry [8, 10–14]. If an N-terminal protecting group is suspected, chemical modification is performed in the usual manner, but $^{2}$H$_{6}$-acetic anhydride is used for Acetylation. Under these conditions, The addition of a $^{2}$H$_{3}$-acetyl group to the N-terminal amino group of the peptide is possible only if it is present in a free state. In the case of an unknown protecting group, its mass is determined from the mass number of the N-terminal ion.



Last update: 06/08/2026

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