Label-free liquid chromatography-tandem mass spectrometry analysis with automated phosphopeptide enrichment reveals dynamic human milk protein phosphorylation during lactation.

ABSTRACT: Protein phosphorylation is a critical posttranslational modification that affects cell-cell signaling and protein function. However, quantifying the relative site-specific changes of phosphorylation occupancies remains a major issue. An online enrichment of phosphopeptides using titanium dioxide incorporated in a microchip liquid chromatography device was used to analyze trypsin-digested human milk proteins with mass spectrometry. The method was validated with standards and used to determine the dynamic behavior of protein phosphorylation in human milk from the first month of lactation. α-Casein, β-casein, osteopontin, and chordin-like protein 2 phosphoproteins were shown to vary during this lactation time in an independent manner. In addition, changes in specific regions of these phosphop

SUBMITTER: Froehlich JW 

PROVIDER: S-EPMC2964395 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature