374 Proteomics Analysis of Human Milk Fat Globule Membrane Proteins

Abstract

BACKGROUND: In the past few years, the main role of human milk in infant nutrition has been progressively recognised not only for nutritional but also for biological aspects. Human milk fat globule membrane protein (HMFGMP) composition is still largely unknown, although accounting for 2–4% of total milk proteins, and contains several important biologically active components. HMFGMPs have been so far poorly studied because of their high hydrophobicity which limits their solubilisation. AIM: This work aimed to update the structural proteome of human MFGMPs and to create an annotated 2-DE database available online. METHODS: human milk from healthy mothers was collected from day 0 to 4 after delivery and pooled. After centrifugation of the specimens, MFGMPs were solubilized and extracted with a double extraction procedure. They were subsequently isolated by two-domensional electrophoresis and investigated by matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-ToF). Identification was performed using three software packages available on the web (Swiss-prot, PeptIdent, MS-Fit and Profound). RESULTS AND DISCUSSION: In this work we have updated the map of the human MFGMPs described in our previous studies, through the identification of 107 proteins among the over 300 spots isolated by 2-DE. The annotated 2-DE map we have elaborated is now available online on http://www.csaapz.to.cnr.it/proteoma/2DE . There is inscreasing evidence of biological functions of MFGMPs: most of these proteins result to have an immunological role (anti-infectious and protective against inflammatory processes) and contribute to the defence mechanisms of the newborn, as well as to the development of the gastroenteral system of infants. CONCLUSIONS: bovine MFGMPs are usually lost during the technological treatments of cow's milk for the preparation of formulated milks for feeding term and preterm infants. The results of this paper on the identification of major MFGMPs will contribute to improve the composition of cow's milk derived infant formulas.