Urea artifacts interfere with immunopurification of lysine acetylation

Urea-based buffers can induce carbamylation artefacts. Here we report that carbamylation of lysine residues resembles the structure of acetylated lysines (K-ac) and compete during K-ac immunoaffinity purification. We propose an alternative strategy using an ionic detergent which improves significantly the selectivity and efficiency of K-ac affinity immuno-purifications.