N- and O-acetylation of threonine residues in the context of proteomics

• Published in: Journal of proteomics Vol. 108; pp. 369 - 372
• Main Authors: Boyer, Jean-Baptiste, Dedieu, Alain, Armengaud, Jean, Verdié, Pascal, Subra, Gilles, Martinez, Jean, Enjalbal, Christine
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 28.08.2014; Elsevier
• Subjects: Acetylation; Chemical Sciences; O-acetyl threonine; Organic chemistry; O–N acetyl transfer; O–N acyl shift; Protein post-translational acetylation; Protein Processing, Post-Translational; Proteins - analysis; Proteins - chemistry; Proteins - metabolism; Proteomics - methods; Threonine - analysis; Threonine - chemistry; Threonine acetylation; O-acetyl threonine; O–N acyl shift; Protein post-translational acetylation; O–N acetyl transfer; Threonine acetylation; O-N acyl shift; O-N acetyl transfer
• ISSN: 1874-3919; 1876-7737
• DOI: 10.1016/j.jprot.2014.06.005

The detection of post-translational modifications (PTMs) of proteins is a matter of intensive research. Among all possible pitfalls that may lead to misidentifications, the chemical stability of modified peptides is scarcely questioned. Global proteomic studies devoted to protein acetylation are becoming popular. Thus, we were concerned about the intrinsic stability of O-acetylated peptides because of the O–N acyl transfer reactivity occurring when an amino moiety is present in the vicinity of the acylated hydroxyl group. Here, the behavior of isomeric O- and N-acetylated, N-terminal threonine-containing peptides was explored in a standard proteomic workflow. We demonstrated a strong chemical instability of O-acetylation, which prevents its detection. The O–N acyl transfer occurring when an amino moiety is present in the vicinity of the acetylated hydroxyl group prevents the distinction of in vivo, post-translational N- and O-acetylation in current proteomic workflows. [Display omitted] •Chemical instability of O-acetylated threonine when present at peptide N-terminus•O–N acetyl transfer occurs in a standard proteomic workflow.•Caution in assigning post-translational modification in acetylome studies