Characterization of the transport system for beta-lactam antibiotics and dipeptides in rat renal brush-border membrane vesicles by photoaffinity labeling.
The uptake of the alpha-aminocephalosporin cephalexin into brush-border membrane vesicles from rat renal cortex was independent on an inward H+-gradient in contrast to the intestinal transport system. The transport system could be irreversibly inhibited by photoaffinity labeling. Two binding polypeptides for beta-lactam antibiotics and dipeptides with apparent molecular weights 130,000 and 95,000 were identified by photoaffinity labeling with [3H]benzylpenicillin and N-(4-azido[3,5-3H]benzoyl) derivatives of cephalexin and glycyl-L-proline. The uptake of cephalexin and the labeling of the respective binding proteins was inhibited by beta-lactam antibiotics and dipeptides as with intestinal brush-border membranes. These data indicate that the transport systems for beta-lactam antibiotics and dipeptides in the brush-border membrane from rat kidney and small intestine are similar but not identical.
Kramer
W
W
Hoechst Aktiengesellschaft, Frankfurt am Main, F.R.G.
Leipe
I
I
Petzoldt
E
E
Girbig
F
F
D000345:Affinity Labels / Q000032:analysis*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism*; D002506:Cephalexin / Q000031:analogs & derivatives / Q000378:metabolism*; D003864:Depression, Chemical; D004151:Dipeptides / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D008871:Microvilli / Q000378:metabolism; D010400:Penicillin G / Q000494:pharmacology; D051381:Rats
D000345:Affinity Labels; D002352:Carrier Proteins; D004151:Dipeptides; D002506:Cephalexin; D010400:Penicillin G