Exocellular beta-lactamases of Streptomyces albus G and strains R39 and K11.
The beta-lactamases excreted by the highly benzylpenicillin-susceptible Streptomyces strain R39 and the highly benzylpenicillin-resistant Streptomyces albus G were isolated and purified. Neither beta-lactamase exhibited dd-carboxypeptidase activity. Both were anionic at pH 8.3, did not require metal ions, and were not sensitive to iodine, but were inhibited by Cu(2+) and readily inactivated by heat. p-Chloromercuribenzoate, iodoacetate, p-aminobenzoate, and substrates and inhibitors of dd-carboxypeptidase had no effect on beta-lactamase activity. The K(m) and V(max) values for beta-lactamase activity were studied with 6-aminopenicillanic acid and with various penicillins and cephalosporins. The beta-lactamase from the related strain K11 of Streptomyces, which is intermediate in its susceptibility to benzylpenicillin, was partially purified, and its activity was compared on the various substrates.
D002268:Carboxypeptidases / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D008826:Microbial Sensitivity Tests; D010400:Penicillin G / Q000494:pharmacology; D010403:Penicillin Resistance; D010405:Penicillinase / Q000302:isolation & purification*; D013302:Streptomyces / Q000187:drug effects / Q000201:enzymology*
D002268:Carboxypeptidases; D010405:Penicillinase; D010400:Penicillin G