Reference : Membrane-bound transpeptidase and penicillin binding sites in Streptomyces strain R61
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
Life sciences : Microbiology
http://hdl.handle.net/2268/83090
Membrane-bound transpeptidase and penicillin binding sites in Streptomyces strain R61
English
Marquet, Alberto [Université de Liège - ULg > Faculté de Médecine, Institut de Botanique > Service de Microbiologie > > >]
Dusart, Jean [Université de Liège - ULg > Faculté de Médecine, Institut de Botanique > Service de Microbiologie > > >]
Ghuysen, Jean-Marie [Université de Liège - ULg > Faculté de Médecine, Institut de Botanique > Service de Microbiologie > > >]
Perkins, Harnold-R. [National Institute for Medical Research > > > > >]
1-Aug-1974
European Journal of Biochemistry
Blackwell Science
46
3
515-523
Yes (verified by ORBi)
International
0014-2956
1432-1033
Oxford
United Kingdom
[en] acyltransferases metabolism ; ampicillin/pharmacology ; binding sites ; binding, competitive ; carbenicillin/pharmacology ; cell membrane/enzymology ; cephalosporins/metabolism/pharmacology ; chromatography, thin layer ; cloxacillin/pharmacology ; electrophoresis, paper ; kinetics ; methicillin/pharmacology ; oxacillin/pharmacology ; penicillin g/*metabolism/pharmacology ; penicillin v/pharmacology ; penicillinase/metabolism ; peptidoglycan/biosynthesis ; protein binding ; streptomyces/*metabolism ; sulfhydryl reagents/pharmacology ; transferases/antagonists & inhibitors
[en] High-affinity penicillin binding sites from which the antibiotic could not be removed by washings at 4°C in 0.017 M K2HPO4 or 0.05 M Tris-HCl pH 7.5, were shown to occur in the isolated membranes of Streptomyces R61. These sites caused the attachment of 25 picomoles of [14C]benzylpenicillin per milligram membrane protein. Penicillins and cephalosporins competed for the same binding sites. The antibiotic concentrations which excluded [14C]benzylpenicillin from 50% of the binding sites were those which inhibited by 50% the membrane-bound transpeptidase. The same rate constant (about 1 × 10−4 s−1) for the dissociation of the benzylpenicillin membrane complex at 37°C and in 0.017 M K2HPO4, was calculated either from the release of the radioactivity (using [14C]benzylpenicillin) or from the recovery of the transpeptidase activity. These observations supported the conclusion that the high-affinity binding sites in the isolated membranes were the transpeptidase molecules. All the complexes formed between the membranes and the various penicillins and cephalosporins examined were reversible at 37°C and in 0.017 M K2HPO4 at least with regard to the transpeptidase. Depending upon the antibiotics, the rate constants for the dissociation of these complexes varied from 3.3 × 10−3 to 0.73 × 10−4 s−1. The radioactivity released through the dissociation of [14C]benzylpenicillin membrane complex occurred mainly in the form of a compound which behaved as [W]-benzylpenicilloic acid both by paper electrophoresis and thin-layer chromatography. It was impossible to choose between several possible mechanisms for the release of the antibiotic molecule.
Fonds de la Recherche Fondamentale Collective
Researchers ; Professionals
http://hdl.handle.net/2268/83090
10.1111/j.1432-1033.1974.tb03645.x

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