Transport properties of bovine and reindeer beta-lactoglobulin in the Caco-2 cell model.
Beta-lactoglobulin (betaLG) is a protein that binds ligands like fatty acids and retinol into the hydrophobic pocket. Our purpose was to study bovine and reindeer betaLG as transporter molecules and compare their transport properties across Caco-2 cell membrane. The reindeer betaLG has more valuable binder characteristics than bovine betaLG because it has only one genetic phenotype and it seems to exhibit better immunological properties. The permeation of betaLG in Caco-2 cells was evaluated by immunoblotting, and the permeation of the model substances retinol, palmitic acid and cholesterol with and without betaLG was determined using [(3)H]-labelled ligands. Both bovine and reindeer betaLG were able to pass across a Caco-2 cell monolayer similarly. Unbound and betaLG-bound [(3)H]retinol and [(3)H]palmitic acid were equally transported across the Caco-2 cell layer, whereas [(3)H]cholesterol could not pass across Caco-2 cells with or without betaLG at any of the studied circumstances. Thus, the bovine and reindeer milk betaLG is not a suitable protein to enhance transport of ligands across the Caco-2 cell membrane, used for predicting intestinal absorption.
Drug Discovery and Development Technology Center, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, FI-00014 Helsinki, Finland.
Laura
L
Riihimäki
Anna
A
Galkin
Moshe
M
Finel
Jonna
J
Heikura
Kaija
K
Valkonen
Vesa
V
Virtanen
Reijo
R
Laaksonen
J Peter
JP
Slotte
Pia
P
Vuorela
D000818:Animals; D001692:Biological Transport; D018938:Caco-2 Cells; D002352:Carrier Proteins / Q000378:metabolism*; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism*; D002784:Cholesterol / Q000378:metabolism; D017097:Electric Impedance; D006801:Humans; D007782:Lactoglobulins / Q000378:metabolism* / Q000493:pharmacokinetics; D008024:Ligands; D019308:Palmitic Acid / Q000378:metabolism; D012053:Reindeer; D014801:Vitamin A / Q000378:metabolism
D002352:Carrier Proteins; D007782:Lactoglobulins; D008024:Ligands; D014801:Vitamin A; D019308:Palmitic Acid; D002784:Cholesterol