Casein phoshopeptides identification by partial-, double-dephosphorylation and endoGluC digestion

The aim of the present study was the development of a relatively simple method without enrichment step to detect, in a mixture of peptides and phosphopeptides, a maximum of CPPs, including multi-phosphorylated and large-size CPPs, by using high pressure liquid chromatography (HPLC), high-resolution mass spectrometry (MS) and bioinformatics. A commercial casein hydrolysate was used as model hydrolysate for this purpose. This approach consisted of use of double and partial dephosphorylations of CPPs as well as digestion by EndoGluC protease before peptidomics analysis.