Qualitative and Quantitative Profiling of Bovine Milk Fat Globule Membrane Protein Fractions

Milk is a biological fluid of unique quality and complexity. It has co-evolved with mammals and mankind to nourish offspring and contains macro- and micronutrients for growth and development of the newborn. Besides casein and whey, both highly concentrated in milk and extensively exploited by the dairy industry, the milk fat globule membrane (MFGM) represents an important fraction rich in bioactive proteins [1]. In order to better understand and subsequently improve functionality of milk products, e.g. infant formulas, detailed qualitative and quantitative protein knowledge of fractions such as MFGM is required. We present label-free proteome profiling and absolute quantification of selected MFGM proteins comparing two sources. Protein quantification is based on mass spectrometric detection of proteotypic peptides [2] via selected reaction monitoring (SRM) approach recently established in the proteomic field.

Novel aspects: Implementation of SRM-based absolute quantification to characterize bioactive MFGM proteins for nutritional applications.

[1]     Dewettinck K., Rombault R., Thienpont N., Le T.T., Messens K., and Van Camp J. (2008) Nutritional and technological aspects of milk fat globule membrane material. Int. Dairy J. 18, 436-457.

[2]    Mallick P., Schirle M., Chen S.C., Flory M.R., Lee H., Martin D., Ranish J., Raught B., Schmitt R., Werner T., Kuster B., and Aebersold R. (2006) Computational prediction of proteotypic peptides for quantitative proteomics. Nature Biotechnology 25, 125-131.