Phosphorylation and coordination bond of mineral inhibit the hydrolysis of the beta-casein (1-25) peptide by intestinal brush-border membrane enzymes.
Caseinophosphopeptides (CPP) are food mineral-rich components that may resist intestinal enzyme hydrolysis. We wondered whether phosphorylation and/or mineral binding induces resistance of CPP to intestinal hydrolysis. We used intestinal brush-border membrane vesicles to digest different forms of the beta-casein (1-25) peptide: unphosphorylated and phosphorylated carrier of varied cations. The results showed that the activity of alkaline phosphatase seems not to be specific to either the phosphorylation degree or the phosphorylation sites whereas phosphorylations limited the action of peptidases. Studying the mechanism and the kinetics of hydrolysis of the different peptides allows understanding how some cations prevent more CPP from hydrolysis than others. The action of both exo- and endopeptidases was limited for the beta-CN (1-25) peptide bound to zinc or copper. Actually the peptide bound to copper was almost not hydrolyzed during the digestion, suggesting that coordination bond of copper to CPP inhibits the action of both phosphatase and peptidases.
Boutrou
Rachel
R
INRA and Agrocampus Ouest, UMR1253 Science et Technologie du Lait et de l'Oeuf, 65 rue de Saint Brieuc, F-35042 Rennes, France. Rachel.Boutrou@rennes.inra.fr
Coirre
Elodie
E
Jardin
Julien
J
Léonil
Joëlle
J
D000469:Alkaline Phosphatase / Q000378:metabolism*; D000818:Animals; D002364:Caseins / Q000378:metabolism*; D015536:Down-Regulation; D006868:Hydrolysis; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000201:enzymology*; D008903:Minerals / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism*; D010766:Phosphorylation; D013552:Swine; D022161:Transport Vesicles / Q000201:enzymology* / Q000235:genetics
D002364:Caseins; D008903:Minerals; D010446:Peptide Fragments; C412562:caseinophosphopeptide 1-25; D000469:Alkaline Phosphatase; D010447:Peptide Hydrolases