Differences in the glycosylation of recombinant and native human milk bile salt-stimulated lipase revealed by peptide mapping.

The milk of some mammals contains a bile salt-stimulated lipase (BSSL). Human milk BSSL is heavily glycosylated (30-40% carbohydrate) and present at a concentration of approximately 100-200 mg/l, thereby being one of the most abundant human whey proteins. BSSL has been shown to have an important role in the uptake of energy from human milk. The risk of HIV contamination has restricted the use of banked human milk for nutritional purposes. This has evoked an interest in the production of a recombinant form of the protein for supplementation of formula. We have produced BSSL in mouse C127 and hamster CHO cells, and used chromatographic methods for the characterization of the products. This study was focused on study of the glycosylation of the protein by using peptide mapping and isolation of glycosylated fragments. The results show how human BSSLs from different sources differ both in extent of glycosylation, in glycan heterogeneity, and in lectin binding.