Protein Chemistry. Structure, Properties, Research Methods - Shendryk A.N. 2022

Methods for Experimental Investigation of Protein Structure
Electron Impact Mass Spectrometry
Introduction to Deuterium-Labeled Peptides

To improve the reliability of determining the Amino Acid Sequence of a peptide, deuterium labels are introduced into it. To obtain deuterated peptide derivatives, D6-acetic anhydride or D3-methyl iodide is used instead of conventional Acetylation and methylation Reagents. Let us consider the practical implications of such a modification. For example, the ion with m/z=126 in THE SPECTRUM OF a conventional permethylated acetylpeptide may belong to an N-terminal pyrrolidonecarboxylic acid residue, an asparagine residue (resulting from N-C bond Cleavage), or an N-terminal Serine residue that has eliminated an ethanol molecule. Analysis of the D-labeled peptide analogue allows this problem to be unambiguously resolved. If the peptide is modified with unlabeled methyl iodide and D6-acetic anhydride, the mass of the ion will remain unchanged in the first two cases, while in the third case, the mass of the ion with m/z=126 will increase to 129. If D3-methyl iodide and unlabeled acetic anhydride are used, ions with m/z = 129 will be formed in the first two cases, and with m/z=132 in the third.



Last update: 06/08/2026

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