Reference : The catalytic activity and penicillin sensitivity in the liquid and frozen states of mem...
Scientific journals : Article
Life sciences : Microbiology
Life sciences : Biochemistry, biophysics & molecular biology
http://hdl.handle.net/2268/83083
The catalytic activity and penicillin sensitivity in the liquid and frozen states of membrane-bound and detergent-solubilised transpeptidase of Streptomyces R61
English
Dusart, Jean [Université de Liège - ULg > Faculté de Médecine, Institut de Botanique > Service de Microbiologie > >]
Marquet, Alberto [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, Harold R [University of Liverpool > Department of Microbiology > > >]
1-Aug-1975
European Journal of Biochemistry
Blackwell Science
56
1
57-65
Yes (verified by ORBi)
International
0014-2956
1432-1033
Oxford
United Kingdom
[en] acyltransferases/*metabolism ; cell membrane/drug effects/enzymology ; detergents/*pharmacology ; enzyme activation/drug effects ; freezing ; hydrogen-ion concentration ; kinetics ; penicillin g/*pharmacology ; peptidyl transferases/*metabolism ; solubility ; streptomyces/*enzymology ; temperature
[en] The Km, app. values of the membrane-bound transpeptidase of Streptomyces R61 for the donor Ac2-L-Lys-D-Ala-D-Ala and the acceptor Gly-Gly are not affected by temperature variations when the reaction mixtures are incubated in liquid suspensions. At -5 degrees C, the incubation can be carried out either in the liquid or in the frozen state. The enzyme is active in the latter state. In the frozen state, the Km, app. value for the acceptor remains unchanged but there is a 3-fold increase in the maximum velocity, a 10-fold decrease of the Km, app. value for the donor and a 10-fold increase of the benzylpenicillin concentration required to inhibit the enzyme activity by 50% (ID50 value). Temperatures of -35 degrees C or below are required to completely inhibit the membrane-bound enzyme in the frozen state. Cetyltrimethylammonium bromide extracts the transpeptidase both from the isolated membranes and, with a much higher yield, from the intact mycelium. The extracted enzyme is not active in the frozen state, requires detergent for activity, has decreased Km, app. values for both donor and acceptor, exhibits the same sensitivity to benzylpenicillin and cephalosporin C as the membrane-bound transpeptidase (in liquid suspensions) and, like this latter enzyme, has no DD-carboxypeptidase activity. The detergent-extracted transpeptidase penetrates gels of Sephadex-100 and is not sedimented at 200 000 X g.
Fonds de la Recherche Fondamentale Collective
Researchers ; Professionals
http://hdl.handle.net/2268/83083

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