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Properties of cephalosporinase from Proteus morganii
Abstract:
The cephalosporin beta-lactamase (cephalosporinase) was purified from a strain of Proteus morganii which showed resistance to cephalosporins. The optimal pH was about 8.5, and the optimal temperature was 40 degrees C. The isoelectric point was 8.7 and the molecular weight was estimated to be about 41,000 from sodium dodecyl sulfate-acrylamide gel electrophoresis. The enzyme activity was inhibited by cloxacillin, ampicillin, carbenicillin, cefuroxime, cefotaxime, ceftizoxime (FK749), cefmenoxime (SCE-1365), cefoxitin, cefmetazole, YM09330 and moxalactam (6059-S), but not by clavulanic acid or CP-45899. The beta-lactamase also hydrolyzed cephaloridine, cefazolin, cephalothin, cephalexin, cefotiam, cefamandole and benzylpenicillin. These results suggest the possibility that the properties of beta-lactamases may be characterized by measuring the kinetic parameters of the enzyme toward newly-introduced beta-lactam antibiotics and beta-lactamase inhibitors.
Insights
Researchers purified cephalosporin beta-lactamase from resistant Proteus morganii. Enzyme properties were characterized, revealing inhibition by specific antibiotics but not clavulanic acid, suggesting new characterization methods.
Area of Science:
- Microbiology
- Biochemistry
- Enzymology
Background:
- Proteus morganii strains can exhibit resistance to cephalosporin antibiotics.
- Beta-lactamases are enzymes responsible for hydrolyzing beta-lactam rings in antibiotics, conferring resistance.
- Understanding the specific properties of beta-lactamases is crucial for developing effective antimicrobial strategies.
Purpose of the Study:
- To purify and characterize the cephalosporin beta-lactamase from a cephalosporin-resistant strain of Proteus morganii.
- To determine the enzyme's optimal conditions, isoelectric point, and molecular weight.
- To investigate the enzyme's susceptibility to various beta-lactam antibiotics and inhibitors.
Main Methods:
- Purification of cephalosporin beta-lactamase from Proteus morganii.
- Determination of optimal pH and temperature for enzyme activity.
- Isoelectric focusing and SDS-PAGE for isoelectric point and molecular weight estimation.
- Enzyme inhibition assays using various beta-lactam antibiotics and inhibitors.
- Substrate hydrolysis assays with different cephalosporins and penicillin.
Main Results:
- The cephalosporin beta-lactamase was successfully purified.
- Optimal activity was observed at pH 8.5 and 40°C, with an isoelectric point of 8.7 and molecular weight of approximately 41,000 Da.
- The enzyme was inhibited by several advanced cephalosporins and other beta-lactams but not by clavulanic acid or CP-45899.
- Hydrolysis was observed for cephaloridine, cefazolin, cephalothin, cephalexin, cefotiam, cefamandole, and benzylpenicillin.
Conclusions:
- The characterized cephalosporin beta-lactamase from Proteus morganii possesses specific inhibitory and substrate hydrolysis profiles.
- Kinetic parameter analysis of beta-lactamases against novel beta-lactam antibiotics and inhibitors can aid in enzyme characterization.
- This study provides insights into antibiotic resistance mechanisms and potential targets for drug development.