title: Glycosylations of kappa-casein-derived caseinomacropeptide reduce its accessibility to endo- but not exointestinal brush border membrane peptidases.
abstract: Caseinomacropeptide (CMP) is a peptide obtained from kappa-casein hydrolysis by gastric proteinases and which exhibits various biological activities. The aim of this study was to analyze the intestinal processing of CMP at the brush border membrane (BBM) level. Intestinal BBM vesicles (BBMV) were used to digest glycosylated and unglycosylated CMP. Our results demonstrated that whatever was the glycosylated state of CMP, they were digested by BBMV intestinal enzymes, from macropeptides to free amino acids. The digestion of unglycosylated and glycosylated CMP throughout the action of exopeptidases was similar, but the activity of endopeptideases on glycosylated CMP was limited, certainly due to the attached O-glycosylations. Consequently, much more peptides were identified from the unglycosylated than from the glycosylated CMP. In addition, the glycosylation core as well as the number of the attached glycosylated chain modified the kinetic of digestion; the most heavily glycosylated forms being the slowest digested.
authors.affiliation: INRA, UMR1253, 65 rue de Saint Brieuc, F-35000 Rennes, France. Rachel.Boutrou@rennes.inra.fr
authors.forename: Rachel
authors.initials: R
authors.lastname: Boutrou
authors.forename: Julien
authors.initials: J
authors.lastname: Jardin
authors.forename: Anne
authors.initials: A
authors.lastname: Blais
authors.forename: Daniel
authors.initials: D
authors.lastname: Tomé
authors.forename: Joëlle
authors.initials: J
authors.lastname: Léonil
mesh_terms: D000818:Animals; D002364:Caseins / Q000737:chemistry / Q000378:metabolism*; D010450:Endopeptidases / Q000378:metabolism*; D020689:Exopeptidases / Q000378:metabolism*; D006031:Glycosylation; D007422:Intestines / Q000201:enzymology*; D007700:Kinetics; D008297:Male; D008871:Microvilli / Q000648:ultrastructure; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D013552:Swine
chemical_list: D002364:Caseins; D010446:Peptide Fragments; C065989:caseinomacropeptide; D010450:Endopeptidases; D020689:Exopeptidases