Title: Interactions between beta-lactam antibiotics and isolated membranes of Streptococcus faecalis ATCC 9790
Authors: Coyette, J ×
Ghuysen, J M
Binot, F
Adriaens, Paul
Meesschaert, B
Vanderhaeghe, Hubert #
Issue Date: 2-Apr-1977
Series Title: European Journal of Biochemistry vol:75 issue:1 pages:231-9
Abstract: The DD-carboxypeptidase-exchange membrane-bound enzyme in Streptococcus faecalis ATCC 9790 reacts with beta-lactam antibiotics to form complexes with rather long half-lives. Depending upon the antibiotic, the second-order rate constants for complex formation range from 0.75-560 M-1 S-1 (at 37 degrees C and in water) and the first-order rate constants for complex breakdown range from 1.3 to 26 x 10(-5) s-1 (at 37 degrees C and in 5 mM phosphate buffer pH 7.5). There are about 30 pmol of DD-carboxypeptidase-exchange enzyme per mg of membrane protein. The degradation products arising from benzylpenicillin are phenylacetylglycine and probably N-formyl-D-penicillamine. Isolated membranes also contain other penicillin binding sites (about 70 pmol/mg membrane protein). That part of benzylpenicillin which reacts with at least some of these latter sites is slowly degraded into penicilloic acid. Normal functioning of the DD-carboxypeptidase-exchange membrane-bound enzyme is important, if not essential, for cell growth. With the beta-lactam antibiotics tested inhibition of cell growth is mainly related to the rates of formation of the inactive enzyme-antibiotic complexes. The relationship, however, is not a direct one probably due to the competitive effect exerted by the other penicillin binding sites.
ISSN: 0014-2956
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Radiology
Medicinal Chemistry (Rega Institute)
× corresponding author
# (joint) last author

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