Commercial aluminium foil could be used to help scientists understand more about important biological pathways. Hubert Girault, at the Federal Polytechnic School of Lausanne, Switzerland, and colleagues used the foil to extract multi-phosphorylated peptides from digested protein mixtures.
Phosphorylation is one of the most important post-translational protein modification procedures. It regulates a wide range of biological processes, such as cell growth. Scientists are keen to learn more about the structure of phosphoproteins and peptides but because they are difficult to ionise (in particular multi-phosphorylated samples) and are present in very small amounts, it is difficult to study them by mass spectrometry (MS). MS usually only detects mono-phosphorylated peptides.
Phosphate has an affinity to metal oxides, such as aluminium oxide, and the more phosphates a peptide contains, the more strongly it is attracted to the oxide. Girault exploited this affinity and used the aluminium foil’s aluminium oxide surface layer to bind only the multi-phosphopeptides from mixtures of milk proteins. The multi-phosphopeptide enriched samples could then be more easily analysed by MS.
Girault says the foil’s selectivity for multi-phosphorylated peptides is very good and comparable with the best known methods using more complex functional materials.
Original publication: Liang Qiao, Hongyan Bi, Jean-Marc Busnel, Mohamad Hojeij, Manuel Mendez, Baohong Liu and Hubert H. Girault, Chem. Sci. 2010.