title: In vivo digestomics of milk proteins in human milk and infant formula using a suckling rat pup model.
abstract: Human milk is the optimal mode of infant feeding for the first several months of life, and infant formulas serve as an alternative when breast-feeding is not possible. Milk proteins have a balanced amino acid composition and some of them provide beneficial bioactivities in their intact forms. They also encrypt a variety of bioactive peptides, possibly contributing to infant health and growth. However, there is limited knowledge of how milk proteins are digested in the gastrointestinal tract and bioactive peptides are released in infants. A peptidomic analysis was conducted to identify peptides released from milk proteins in human milk and infant formula, using a suckling rat pup model. Among the major milk proteins targeted, α-lactalbumin and β-casein in human milk, and β-lactoglobulin and β-casein in infant formula were the main sources of peptides, and these peptides covered large parts of the parental proteins' sequences. Release of peptides was concentrated to specific regions, such as residues 70-92 of β-casein in human milk, residues 39-55 of β-lactoglobulin in infant formula, and residues 57-96 and 145-161 of β-CN in infant formula, where resistance to gastrointestinal digestion was suggested. In the context of bioactive peptides, release of fragments containing known bioactive peptides was confirmed, such as β-CN-derived opioid and antihypertensive peptides. It is therefore likely that these fragments are of biological significance in neonatal health and development.
authors.affiliation: Department of Nutrition, University of California, Davis, One Shields Ave., Davis, CA 95616, USA; Nutritional Science Institute, Morinaga Milk Industry Co., Ltd., 5-1-83, Higashihara, Zama, Kanagawa-Pref. 252-8583, Japan.
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Wada
authors.affiliation: Genome Center Proteomics Core Facility, University of California, Davis, 451 E. Health Sciences Dr., Davis, CA 95616, USA.
authors.forename: Brett S
authors.initials: BS
authors.lastname: Phinney
authors.affiliation: Genome Center Proteomics Core Facility, University of California, Davis, 451 E. Health Sciences Dr., Davis, CA 95616, USA.
authors.forename: Darren
authors.initials: D
authors.lastname: Weber
authors.affiliation: Department of Nutrition, University of California, Davis, One Shields Ave., Davis, CA 95616, USA. Electronic address: bllonnerdal@ucdavis.edu.
authors.forename: Bo
authors.initials: B
authors.lastname: Lönnerdal
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D002364:Caseins / Q000737:chemistry / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007223:Infant; D041943:Infant Formula; D007781:Lactoferrin / Q000737:chemistry / Q000378:metabolism; D007782:Lactoglobulins / Q000737:chemistry / Q000378:metabolism; D008894:Milk Proteins / Q000737:chemistry / Q000302:isolation & purification*; D008895:Milk, Human / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification; D059748:Proteolysis; D051381:Rats
chemical_list: D000596:Amino Acids; D002364:Caseins; D007782:Lactoglobulins; D008894:Milk Proteins; D010455:Peptides; D007781:Lactoferrin
keywords: Bioactive peptides; Human milk; Infant formula; Milk proteins; Suckling rat pups