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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
2
|
| pubmed:dateCreated |
1987-6-12
|
| pubmed:abstractText |
The characteristics of the transport of cefixime, a new p.o. cephalosporin, antibiotic, were studied by using brush-border membrane vesicles from the rat small intestine. The initial rate of uptake of cefixime was not affected by the presence of an inward gradient of either Na+ or other monovalent cations. With an intravesicular pHi of 7.5, optimal cefixime uptake occurred at an extravesicular pHo of 5.0, with about 6-fold acceleration compared with that in the absence of an inward proton gradient (pHi = pHo = 7.5). A protonophore, carbonyl-cyanide-4-trifluoromethoxy-phenylhydrazone, abolished the stimulating effect of low pHo. In the presence of a sufficient inward proton gradient (pHi = 7.5, pHo = 5.0), cefixime uptake showed an overshoot phenomenon and apparent saturation kinetics expressed by the Michaelis-Menten equation with the maximum rate of 2.67 +/- 0.06 nmol/30 sec/mg of protein and a Michaelis constant of 0.83 +/- 0.04 mM. Cefixime uptake was inhibited competitively by glycyl-L-proline and stimulated by the countertransport effect of this dipeptide. The other peptides also inhibited cefixime uptake significantly. A valinomycin-induced inside-negative K+-diffusion potential had a dramatic reducing effect on the uptake of dianionic cefixime. All the data obtained in this study demonstrate that cefixime transport across the brush-border membrane vesicles is carrier-mediated, independent of Na+ and dependent on a H+ gradient via the peptide transport systems.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Amino Acids,
http://linkedlifedata.com/resource/pubmed/chemical/Carbonyl Cyanide...,
http://linkedlifedata.com/resource/pubmed/chemical/Cefixime,
http://linkedlifedata.com/resource/pubmed/chemical/Cefotaxime,
http://linkedlifedata.com/resource/pubmed/chemical/Dipeptides,
http://linkedlifedata.com/resource/pubmed/chemical/Oligopeptides,
http://linkedlifedata.com/resource/pubmed/chemical/glycylproline
|
| pubmed:status |
MEDLINE
|
| pubmed:month |
May
|
| pubmed:issn |
0022-3565
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
241
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
594-601
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading |
pubmed-meshheading:3572815-Amino Acids,
pubmed-meshheading:3572815-Animals,
pubmed-meshheading:3572815-Biological Transport, Active,
pubmed-meshheading:3572815-Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone,
pubmed-meshheading:3572815-Cefixime,
pubmed-meshheading:3572815-Cefotaxime,
pubmed-meshheading:3572815-Dipeptides,
pubmed-meshheading:3572815-Hydrogen-Ion Concentration,
pubmed-meshheading:3572815-Intestine, Small,
pubmed-meshheading:3572815-Kinetics,
pubmed-meshheading:3572815-Male,
pubmed-meshheading:3572815-Mathematics,
pubmed-meshheading:3572815-Membrane Potentials,
pubmed-meshheading:3572815-Microvilli,
pubmed-meshheading:3572815-Oligopeptides,
pubmed-meshheading:3572815-Osmolar Concentration,
pubmed-meshheading:3572815-Rats,
pubmed-meshheading:3572815-Rats, Inbred Strains,
pubmed-meshheading:3572815-Temperature
|
| pubmed:year |
1987
|
| pubmed:articleTitle |
H+ gradient-dependent and carrier-mediated transport of cefixime, a new cephalosporin antibiotic, across brush-border membrane vesicles from rat small intestine.
|
| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|