We describe here a simple procedure for greatly reducing contamination of nuclear extracts by naturally biotinylated cytoplasmic carboxylases, which represent a major source of non-specific background when employing BirA-mediated biotinylation tagging for the purification and characterization of nuclear protein complexes by mass spectrometry. We show that the use of 0.5% of the non-ionic detergent Nonidet-40 (NP-40) during cell lysis and nuclei isolation is sufficient to practically eliminate contamination of nuclear extracts by carboxylases and to greatly reduce background signals in downstream mass spectrometric analyses.

doi.org/10.1016/j.pep.2013.02.015, hdl.handle.net/1765/66384
Protein Expression and Purification
Department of Biochemistry

Papageorgiou, D., Demmers, J., & Strouboulis, J. (2013). NP-40 reduces contamination by endogenous biotinylated carboxylases during purification of biotin tagged nuclear proteins. Protein Expression and Purification, 89(1), 80–83. doi:10.1016/j.pep.2013.02.015