title: Purification by p-aminobenzoic acid (PABA)-affinity chromatography and the functional reconstitution of the nateglinide/H+ cotransport system in the rat intestinal brush-border membrane.
abstract: (-)-N-(trans-4-isopropylcyclohexanecarbonyl)-D-phenylalanine (nateglinide) is a novel oral hypoglycemic agent possessing a peptide-type bond and a carboxyl group in its structure. Recently, we have shown that nateglinide transport occurs via the ceftibuten/H+ cotransport system, which is distinct from PepT1, and that the fluorescein/H+ cotransport system is involved in the uptake of nateglinide. The aim of this study was to characterize the functional properties of the intestinal nateglinide transporter. In the first part of this study, we demonstrated that the ceftibuten/H+ cotransport system is identical to the fluorescein/H+ cotransport system. We succeeded in purification of the nateglinide transporter from brush-border membranes of the rat small intestine using p-aminobenzoic acid (PABA)-affinity chromatography. We then investigated the functional properties of the nateglinide transporter using proteoliposomes prepared from the PABA-affinity chromatography elute. We demonstrated that nateglinide, ceftibuten, and fluorescein are transported by the same transporter in the intestine.
authors.affiliation: Department of Clinical Pharmaceutics and Therapeutics, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita 12-jo, Nishi 6-chome, Kita-ku, Sapporo 060-0812, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Saito
authors.forename: Shirou
authors.initials: S
authors.lastname: Itagaki
authors.forename: Sayaka
authors.initials: S
authors.lastname: Kubo
authors.forename: Masaki
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hirano
authors.forename: Ken
authors.initials: K
authors.lastname: Iseki
mesh_terms: D010129:4-Aminobenzoic Acid / Q000737:chemistry*; D000818:Animals; D019817:Benzoic Acid / Q000737:chemistry; D001692:Biological Transport; D000077722:Ceftibuten; D002462:Cell Membrane / Q000378:metabolism*; D002511:Cephalosporins / Q000737:chemistry*; D002846:Chromatography, Affinity / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D003510:Cyclohexanes / Q000737:chemistry*; D004147:Dioxins / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D017886:Durapatite / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D019793:Fluorescein / Q000737:chemistry; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000378:metabolism; D007421:Intestine, Small / Q000378:metabolism; D008081:Liposomes / Q000737:chemistry; D008297:Male; D008871:Microvilli / Q000187:drug effects* / Q000378:metabolism*; D000077715:Nateglinide; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000737:chemistry; D011510:Proteolipids / Q000737:chemistry; D011522:Protons; D051381:Rats; D017208:Rats, Wistar; D020156:Salicylic Acid / Q000737:chemistry; D014466:Ultraviolet Rays
chemical_list: D002511:Cephalosporins; D003510:Cyclohexanes; D004147:Dioxins; D007004:Hypoglycemic Agents; D008081:Liposomes; D011510:Proteolipids; D011522:Protons; C020485:proteoliposomes; D000077715:Nateglinide; D010649:Phenylalanine; D019817:Benzoic Acid; D017886:Durapatite; D000077722:Ceftibuten; D020156:Salicylic Acid; D010129:4-Aminobenzoic Acid; D019793:Fluorescein