Abstract | Characterization of the major human milk fat globular membrane proteins was carried out using proteomic techniques comprising two-dimensional polyacrylamide gel electrophoresis, followed by in situ PNGase F and trypsin digestion. Matrix-assisted laser desorption/ionization quadropole time-of-flight and electrospray ionization mass spectrometry identified seven major protein components: α-lactalbumin, lysozyme precursor, β-casein, clusterin, lactotransferrin, polymeric immunoglobulin receptor precursor, and human milk fat globule EGF-factor 8 protein. Sequence information on the protein-associated glycans was determined by matrix-assisted laser desorption-ionization quadropole time-of-flight hybrid mass spectrometry. This glycan analysis revealed interesting fucosylation branching patterns which may be influential in maternal protection of the newborn against bacterial and viral pathogenic attack. |
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