Abstract
The multiple stages of derepression of the type I chromosomal beta-lactamase in Pseudomonas aeruginosa were examined. Mutants partially and fully derepressed for beta-lactamase were selected from a wild-type clinical isolate. An analysis of the beta-lactamase produced by these mutants and the induced wild type revealed significant differences in the products of derepression at each stage. Beta-lactamase produced by the fully derepressed mutant showed a lower affinity (K(m), 0.113 mM) for cephalothin than that produced by the partially derepressed mutant (K(m), 0.049 mM). However, due to a very large V(max), the former possessed a much greater hydrolytic efficiency. Differences in substrate profile were also noted. Only beta-lactamase from the fully derepressed mutant hydrolyzed cefamandole, cefoperazone, and cefonicid. The partially derepressed mutant possessed a single beta-lactamase band with a pI of 8.4. The fully derepressed mutant possessed this band and an additional major band with a pI of 7.5. Induction of the wild type with cefoxitin produced both bands. The changes in physiologic parameters of the enzymes produced in the different stages of derepression suggest a complex system for beta-lactamase expression in P. aeruginosa. This may involve at least two distinct structural regions, each of which is under control of the same repressor.
| Original language | English |
|---|---|
| Pages (from-to) | 453-457 |
| Number of pages | 5 |
| Journal | Antimicrobial Agents and Chemotherapy |
| Volume | 30 |
| Issue number | 3 |
| State | Published - 1986 |
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All Science Journal Classification (ASJC) codes
- Pharmacology (medical)
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Evidence for multiple forms of type I chromosomal β-lactamase in Pseudomonas aeruginosa. / Gates, M. L.; Sanders, C. C.; Goering, Richard V.; Sanders, W. E.
In: Antimicrobial Agents and Chemotherapy, Vol. 30, No. 3, 1986, p. 453-457.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Evidence for multiple forms of type I chromosomal β-lactamase in Pseudomonas aeruginosa
AU - Gates, M. L.
AU - Sanders, C. C.
AU - Goering, Richard V.
AU - Sanders, W. E.
PY - 1986
Y1 - 1986
N2 - The multiple stages of derepression of the type I chromosomal beta-lactamase in Pseudomonas aeruginosa were examined. Mutants partially and fully derepressed for beta-lactamase were selected from a wild-type clinical isolate. An analysis of the beta-lactamase produced by these mutants and the induced wild type revealed significant differences in the products of derepression at each stage. Beta-lactamase produced by the fully derepressed mutant showed a lower affinity (K(m), 0.113 mM) for cephalothin than that produced by the partially derepressed mutant (K(m), 0.049 mM). However, due to a very large V(max), the former possessed a much greater hydrolytic efficiency. Differences in substrate profile were also noted. Only beta-lactamase from the fully derepressed mutant hydrolyzed cefamandole, cefoperazone, and cefonicid. The partially derepressed mutant possessed a single beta-lactamase band with a pI of 8.4. The fully derepressed mutant possessed this band and an additional major band with a pI of 7.5. Induction of the wild type with cefoxitin produced both bands. The changes in physiologic parameters of the enzymes produced in the different stages of derepression suggest a complex system for beta-lactamase expression in P. aeruginosa. This may involve at least two distinct structural regions, each of which is under control of the same repressor.
AB - The multiple stages of derepression of the type I chromosomal beta-lactamase in Pseudomonas aeruginosa were examined. Mutants partially and fully derepressed for beta-lactamase were selected from a wild-type clinical isolate. An analysis of the beta-lactamase produced by these mutants and the induced wild type revealed significant differences in the products of derepression at each stage. Beta-lactamase produced by the fully derepressed mutant showed a lower affinity (K(m), 0.113 mM) for cephalothin than that produced by the partially derepressed mutant (K(m), 0.049 mM). However, due to a very large V(max), the former possessed a much greater hydrolytic efficiency. Differences in substrate profile were also noted. Only beta-lactamase from the fully derepressed mutant hydrolyzed cefamandole, cefoperazone, and cefonicid. The partially derepressed mutant possessed a single beta-lactamase band with a pI of 8.4. The fully derepressed mutant possessed this band and an additional major band with a pI of 7.5. Induction of the wild type with cefoxitin produced both bands. The changes in physiologic parameters of the enzymes produced in the different stages of derepression suggest a complex system for beta-lactamase expression in P. aeruginosa. This may involve at least two distinct structural regions, each of which is under control of the same repressor.
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M3 - Article
VL - 30
SP - 453
EP - 457
JO - Antimicrobial Agents and Chemotherapy
JF - Antimicrobial Agents and Chemotherapy
SN - 0066-4804
IS - 3
ER -