Identification of Na+,Pi-binding protein in kidney and intestinal brush-border membranes.
An Na+, Pi-binding protein has been extracted from kidney and intestinal brush-border membranes with an organic solvent and has been purified by Kieselghur and Sephadex LH-60 chromatography. The molecular mass of this protein has been estimated to be about 155 kDa as determined by gel-filtration chromatography on Sepharose 2B. Under denaturing conditions, polyacrylamide-gel electrophoresis revealed a monomer of molecular mass about 70 kDa. The protein has high specificity and high affinity for Pi [K0.5 (concentration at which half-maximal binding is observed) near 10 microM]. Na2+ binding also exhibits saturation behaviour, with a K0.5 near 7.5 mM. Pi binding is inhibited by known inhibitors of Pi transport in brush-border membrane vesicles. It appears that this protein could be involved in Na+/Pi co-transport across the renal and intestinal brush-border membranes.
Debiec
H
H
Department of Biochemistry and Experimental Medicine, Hospital Monument Child's Health Center, Warsaw, Poland.
Lorenc
R
R
D000818:Animals; D000838:Anions / Q000494:pharmacology; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002850:Chromatography, Gel; D002855:Chromatography, Thin Layer; D004591:Electrophoresis, Polyacrylamide Gel; D007413:Intestinal Mucosa / Q000378:metabolism*; D007672:Kidney Cortex / Q000378:metabolism*; D008297:Male; D008871:Microvilli / Q000187:drug effects / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism / Q000493:pharmacokinetics; D011485:Protein Binding / Q000187:drug effects; D011817:Rabbits; D012964:Sodium / Q000494:pharmacology; D050608:Sodium-Phosphate Cotransporter Proteins; D027981:Symporters
D000838:Anions; D002352:Carrier Proteins; D010710:Phosphates; D050608:Sodium-Phosphate Cotransporter Proteins; D027981:Symporters; D012964:Sodium