[en] Kinetically, the three-step model proposed for the interaction between beta-lactam antibiotics and the exocellular DD-carboxypeptidases-transpeptidases of Streptomyces R61 and Actinomadura R39 [Frère, Ghuysen & Iwatsubo (1975) Eur. J. Biochem. 57, 343--357; Fuad, Frère, Ghuysen, Duez & Iwatsubo (1976) Biochem. J. 155, 623--629] applies to the interaction between the much less penicillin-sensitive exocellular DD-carboxypeptidase-endopeptidase of Streptomyces albus G and at least phenoxymethylpenicillin, cephalothin and cephalosporin C. The penicillin resistance of the albus G enzyme is mainly due to the low efficiency with which the first reversible complex formed with the antibiotic (complex EI) undergoes transformation into a second more stable complex EI*. Analysis of the ternary interaction between enzyme, NalphaNepsilon-diacetyl-L-lysyl-D-alanyl-D-alanine (Ac2-L-Lys-D-Ala-D-Ala) and cephalosporin C indicates a non-competitive mechanism.
Disciplines :
Biochemistry, biophysics & molecular biology
Author, co-author :
Frère, Jean-Marie ; Université de Liège - ULiège > Faculté de Médecine, Institut de Botanique > Service de Microbiologie
Geurts, Francine; Université de Liège - ULiège > Faculté de Médecine, Institut de Botanique > Service de Microbiologie
Ghuysen, Jean-Marie ; Université de Liège - ULiège > Faculté de Médecine, Institut de Botanique > Service de Microbiologie
Language :
English
Title :
The exocellular DD-carboxypeptidase-endopeptidase of Streptomyces albus G. Interaction with beta-lactam antibiotics.
