Special Issue Article
Protein-Linked Glycan Degradation in Infants Fed Human Milk
- *Corresponding Author:
- David C. Dallasc
Department of Food Science and Technology
University of California at Davis
One Shields Avenue, Davis, CA
Tel: (530) 752-1057l
Fax: (530) 752-4759
E-mail: [email protected]
Received date: April 05, 2012; Accepted date: April 28, 2012; Published date: May 01, 2012
Citation: Dallas DC, Sela D, Underwood MA, German JB, Lebrilla C (2012) Protein-Linked Glycan Degradation in Infants Fed Human Milk. J Glycomics Lipidomics S1:002. doi: 10.4172/2153-0637.S1-002
Copyright: © 2012 Dallas DC, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Many human milk proteins are glycosylated. Glycosylation is important in protecting bioactive proteins and peptide fragments from digestion. Protein-linked glycans have a variety of functions; however, there is a paucity of information on protein-linked glycan degradation in either the infant or the adult digestive system. Human digestive enzymes can break down dietary disaccharides and starches, but most of the digestive enzymes required for complex protein-linked glycan degradation are absent from both human digestive secretions and the external brush border membrane of the intestinal lining. Indeed, complex carbohydrates remain intact throughout their transit through the stomach and small intestine, and are undegraded by in vitro incubation with either adult pancreatic secretions or intact intestinal brush border membranes. Human gastrointestinal bacteria, however, produce a wide variety of glycosidases with regio- and anomeric specificities matching those of protein-linked glycan structures. These bacteria degrade a wide array of complex carbohydrates including various protein-linked glycans. That bacteria possess glycan degradation capabilities, whereas the human digestive system, perse, does not, suggests that most dietary protein-linked glycan breakdown will be of bacterial origin. In addition to providing a food source for specific bacteria in the colon, protein-linked glycans from human milk may act as decoys for pathogenic bacteria to prevent invasion and infection of the host. The composition of the intestinal microbiome may be particularly important in the most vulnerable humans-the elderly, the immunocompromised, and infants (particularly premature infants).