Characteristics of Aerobacter beta-lactamase

1968 ◽  
Vol 14 (2) ◽  
pp. 139-145 ◽  
Author(s):  
M. Goldner ◽  
D. G. Glass ◽  
P. C. Fleming
Keyword(s):  
Reaction Rates ◽  
Penicillin G ◽  
Cephalosporin C ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Lactam Ring ◽  
Rate Of Hydrolysis ◽  
High Concentrations ◽  
Hydrolysis Of ◽  
Pseudomonas Pyocyanea

In this investigation, Aerobacter cloacae is shown to inactivate cephalosporin by hydrolysis of its beta-lactam ring. This was demonstrated by iodine absorption and infrared absorption spectra.The values of the Michaelis constant obtained with cephalosporin C and deacetyl cephalosporin C indicate a great affinity of the Aerobacter's beta-lactamase for its substrate. The enzyme was most active at pH 7.0 and 37 C. Aqueous washings of the Aerobacter cells were a potent source of enzyme.The beta-lactamase of A. cloacae was active on both cephalosporin and penicillin. A higher rate of hydrolysis was observed with cephalosporin C and deacetyl cephalosporin C than with cephalothin and cephaloridine. The ratio of reaction rates on cephalosporin C to that on penicillin G was consistently of the order of 100 to 1. The activity on V, N, and especially the semisynthetic penicillins was also low.The A. cloacae enzyme was easily demonstrable in large amount without added inducer. By contrast, the activity of the beta-lactamase from Pseudomonas pyocyanea cannot be detected unless high concentrations of inducer are used.

scholarly journals A metallo-beta-lactamase with both beta-lactamase and ribonuclease activity is linked with traduction in giant viruses

2019 ◽  
Author(s):  
Philippe Colson ◽  
Lucile Pinault ◽  
Said Azza ◽  
Nicholas Armstrong ◽  
Eric Chabriere ◽  
...  
Keyword(s):  
Acanthamoeba Castellanii ◽  
Deep Ocean ◽  
Penicillin G ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Strong Activity ◽  
Beta Lactam Antibiotics ◽  
Double Stranded Dna ◽  
Giant Viruses ◽  
Hydrolysis Of

ABSTRACTEnzymatic proteins with a metallo-beta-lactamase (MBL) fold have been essentially studied in bacteria for their activity on beta-lactam antibiotics. However, the MBL fold is ancient and highly conserved, and these proteins are capable of cleaving a broad range of substrates. It has recently been shown that MBLs are present in a wide array of cellular organisms, including eukaryotes and archaea. We show here that Tupanvirus deep ocean, a giant virus, also encodes a protein with a MBL fold. Phylogeny showed its clustering with transfer ribonucleases (RNases) and the presence of orthologs in other giant viruses, mainly those harboring the largest sets of translation components. In addition, it suggests an ancient origin for these genes and a transfer between giant viruses and Acanthamoeba spp., a host of many giant viruses. Biologically, after its expression in Escherichia coli, the tupanvirus protein was found to hydrolyse nitrocefin, a chromogenic beta-lactam. We also observed an hydrolysis of penicillin G (10 μg/mL) and detected the metabolite of penicillin G hydrolysis, benzylpenilloic acid. This was inhibited by sulbactam, a beta-lactamase inhibitor. In addition, we tested the degradation of single-stranded DNA, double-stranded DNA, and RNAs, and observed a strong activity on RNAs from seven bacteria with G+C varying from 42% to 67%, and from Acanthamoeba castellanii, the tupanvirus host. This was not inhibited by sulbactam or ceftriaxone. RNase activity was estimated to be 0.45±0.15 mU/mg using a fluorescence-based assay. Our results still broaden the range of hosts of MBL fold proteins and demonstrate that such protein can have dual beta-lactamase/nuclease activities. We suggest that they should be annotated according to this finding to avoid further confusion.

scholarly journals Mechanism of acyl transfer by the class A serine β-lactamase of Streptomyces albus G

1991 ◽  
Vol 279 (1) ◽  
pp. 213-221 ◽  
Author(s):  
J Lamotte-Brasseur ◽  
G Dive ◽  
O Dideberg ◽  
P Charlier ◽  
J M Frère ◽  
...  
Keyword(s):  
Carbon Atom ◽  
Amide Bond ◽  
Carbonyl Carbon Atom ◽  
Cephalosporin C ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Carbonyl Carbon ◽  
Class A ◽  
Streptomyces Albus ◽  
Hydrolysis Of

Optimization by energy minimization of stable complexes occurring along the pathway of hydrolysis of benzylpenicillin and cephalosporin C by the Streptomyces albus G beta-lactamase has highlighted a proton shuttle that may explain the catalytic mechanism of the beta-lactamases of class A. Five residues, S70, S130, N132, T235 and A237, are involved in ligand binding. The gamma-OH group of T235 and, in the case of benzylpenicillin, the gamma-OH group of S130 interact with the carboxylate group, on one side of the ligand molecule. The side-chain NH2 group of N132 and the carbonyl backbone of A237 interact with the exocyclic CONH amide bond, on the other side of the ligand. The backbone NH groups of S70 and A237 polarize the carbonyl group of the scissile beta-lactam amide bond. Four residues, S70, K73, S130 and E166, and two water molecules, W1 and W2, perform hydrolysis of the bound beta-lactam compound. E166, via W1, abstracts the proton from the gamma-OH group of S70. While losing its proton, the O-gamma atom of S70 attacks the carbonyl carbon atom of the beta-lactam ring and, concomitantly, the proton is delivered back to the adjacent nitrogen atom via W2, K73 and S130, thus achieving formation of the acyl-enzyme. Subsequently, E166 abstracts a proton from W1. While losing its proton, W1 attacks the carbonyl carbon atom of the S70 ester-linked acyl-enzyme and, concomitantly, re-entry of a water molecule W'1 replacing W1 allows E166 to deliver the proton back to the same carbonyl carbon atom, thus achieving hydrolysis of the beta-lactam compound and enzyme recovery. The model well explains the differences found in the kcat. values for hydrolysis of benzylpenicillin and cephalosporin C by the Streptomyces albus G beta-lactamase. It also explains the effects caused by site-directed mutagenesis of the Bacillus cereus beta-lactamase I [Gibson, Christensen & Waley (1990) Biochem J. 272, 613-619].

Examination of various Gram-negative bacteria for beta-lactamase activity

1968 ◽  
Vol 14 (5) ◽  
pp. 601-603 ◽  
Author(s):  
Pragna Desai ◽  
M. Goldner
Keyword(s):  
Quantitative Data ◽  
Direct Evidence ◽  
Bacterial Species ◽  
Penicillin G ◽  
Gram Negative Bacteria ◽  
Beta Lactamase ◽  
Infrared Spectrophotometry ◽  
Beta Lactam ◽  
Lactam Ring

The beta-lactamase activity in 10 bacterial species from different genera were evaluated where direct evidence and quantitative data were lacking. A quantitative iodometric method and infrared spectrophotometry were used for the determination of the beta-lactamase activity. The organisms tested were shown to have enzyme activity directed against the beta-lactam ring, and on the basis of the activity on two members of the beta-lactam group of antibiotics, penicillin G and cephalosporin C, a particular ratio was obtained for each species. This report supports the fact of the widespread distribution of beta-lactamase and reopens the question of its significance.

scholarly journals Inhibition of class C β-lactamases by (1′R,6R)-6-(1′-hydroxy)benzylpenicillanic acid SS-dioxide

1985 ◽  
Vol 225 (2) ◽  
pp. 435-439 ◽  
Author(s):  
G C Knight ◽  
S G Waley
Keyword(s):  
Side Chain ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Beta Lactamases ◽  
Beta Lactam Antibiotics ◽  
Lactam Ring ◽  
Class C ◽  
Hydrolysis Of

beta-Lactamases, enzymes that catalyse the hydrolysis of the beta-lactam ring in beta-lactam antibiotics, are divided into three classes, A, B and C, on the basis of the structures so far determined. There are relatively few effective inhibitors of class C beta-lactamases. A beta-lactam sulphone with a hydroxybenzyl side chain, namely (1′R,6R)-6-(1′-hydroxy)benzylpenicillanic acid SS-dioxide (I), has now been studied. The sulphone is a good mechanism-based inhibitor of class C beta-lactamases. At pH8, the inhibition of a Pseudomonas beta-lactamase is irreversible, and proceeds at a rate that is about one-tenth the rate of concurrent hydrolysis. The labelled enzyme has enhanced u.v. absorption and is probably an enamine. At a lower pH, however, inhibition is transitory.

scholarly journals PREVALENCE OF CEPHALOSPORIN-RESISTANT GRAM-NEGATIVE BACILLI FROM CLINICAL SAMPLES

2016 ◽  
pp. 176
Author(s):  
Kavi Aniis ◽  
Rajamanikandan Kcp ◽  
Arvind Prasanth D
Keyword(s):  
Clinical Samples ◽  
Beta Lactamase ◽  
Bacterial Isolates ◽  
Beta Lactam ◽  
Gram Negative ◽  
Beta Lactamases ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Lactam Ring ◽  
Esbl Producers

<p>ABSTRACT<br />Objective: Beta-lactams are the group of antibiotics that contain a ring called as “beta-lactam ring,” which is responsible for the antibacterial activity.<br />The presence of resistance among Gram-negative organisms is due to the production of beta-lactamases enzymes that hydrolysis the beta-lactam ring<br />thereby conferring resistance to the organism. This study is undertaken to determine the prevalence of extended-spectrum beta-lactamase (ESBL)<br />producing Gram-negative organism from clinical samples.<br />Methods: A total of 112 clinical samples were taken for this study. The combined disc synergistic test (CDST) was used for the phenotypic detection<br />of ESBL producers from the clinical samples. The genotypic identification of ESBL producers was carried out by alkaline lysis method by isolation of<br />plasmid DNA.<br />Result: A total of 87 bacterial isolates were isolated and identified. Among them, Klebsiella (41%) was the predominant organism followed by<br />Escherichia coli (33%), Proteus (10%), Pseudomonas (10%), and Serratia (6%). Among the various bacterial isolates, Klebsiella showed a higher<br />percentage of resistance. The CDST showed that 8 isolates of Klebsiella, 3 isolates of E. coli, and 1 isolate of Pseudomonas were found to be ESBL<br />producers. The genotypic confirmation showed that the two bacterial isolates, namely, Klebsiella and E. coli were found to possess temoniera (TEM)<br />gene which was the 400-500 bp conferring resistance to the antibiotics.<br />Conclusion: The results of this study suggest that early detection of ESBL producing Gram-negative organism is a very important step in planning the<br />therapy of patient in Hospitals. CDST continues to be a good indicator in the detection of ESBL producers.<br />Keywords: Beta-lactamases, Gram-negative bacilli, Extended-spectrum beta-lactamase, Resistance, Combined disc synergistic test.</p><p> </p>

scholarly journals The stereochemistry of β-lactam formation in cephalosporin biosynthesis

1978 ◽  
Vol 169 (3) ◽  
pp. 705-707 ◽  
Author(s):  
J A Huddleston ◽  
E P Abraham
Keyword(s):  
Cephalosporin C ◽  
Cephalosporium Acremonium ◽  
Beta Lactam ◽  
Lactam Ring

3H and 14C from (2R,3S)[U-14C,3-3H1]cysteine and (2R,3R)-[U-14C,2,3-3H2]cysteine were incorporated into cephalosporin C by Cephalosporium acremonium. Analysis of the radioactive cephalosporin C indicated that the formation of its beta-lactam ring occurs stereospecifically and with retention of configuration at C-3 of cysteine.

scholarly journals Substrate-induced inactivation of the OXA2 β-lactamase

1993 ◽  
Vol 295 (3) ◽  
pp. 871-878 ◽  
Author(s):  
P Ledent ◽  
J M Frère
Keyword(s):  
Competitive Inhibition ◽  
Hydrolysis Product ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Hydrolysis Time ◽  
Beta Lactam Antibiotics ◽  
Class D ◽  
Time Courses ◽  
Burst Kinetics ◽  
Hydrolysis Of

The hydrolysis time courses of 22 beta-lactam antibiotics by the class D OXA2 beta-lactamase were studied. Among these, only three appeared to correspond to the integrated Henri-Michaelis equation. ‘Burst’ kinetics, implying branched pathways, were observed with most penicillins, cephalosporins and with flomoxef and imipenem. Kinetic parameters characteristic of the different phases of the hydrolysis were determined for some substrates. Mechanisms generally accepted to explain such reversible partial inactivations involving branches at either the free enzyme or the acyl-enzyme were inadequate to explain the enzyme behaviour. The hydrolysis of imipenem was characterized by the occurrence of two ‘bursts’, and that of nitrocefin by a partial substrate-induced inactivation complicated by a competitive inhibition by the hydrolysis product.

Penicillin Update

1995 ◽  
Vol 16 (3) ◽  
pp. 83-90
Author(s):  
Stuart L. Goldstein ◽  
Sheldon L. Kaplan ◽  
Ralph D. Feigin
Keyword(s):  
Cell Wall ◽  
Mechanism Of Action ◽  
Antimicrobial Agents ◽  
Specific Activity ◽  
Basic Structure ◽  
Penicillin G ◽  
Side Chain ◽  
Beta Lactam ◽  
Lactam Ring ◽  
The Stability

Penicillin was discovered serendipitously by Alexander Fleming in 1928 while he was examining Staphylococcus variants. The first trials of penicillin in humans who had serious staphylococcal infections were undertaken more than I decade later and yielded impressive therapeutic results. Despite the introduction of numerous other antimicrobial agents and the emergence of many organisms resistant to penicillin, this agent remains a powerful and essential antibiotic 50 years after its first clinical application. Pharmacology The basic structure of the penicillins consists of the thiazolidine ring, a beta-lactam ring, and a side chain (Figure 1). The antimicrobial activity of all penicillins is produced by the thiazolidine/beta-lactam nucleus, and the organism-specific activity of a particular penicillin is determined by the side chain derivative. There are many naturally occurring side chain derivatives, but penicillin G is the most potent of these and, therefore, the only one used clinically. Semisynthetic penicillins are constructed from the basic penicillin nucleus with a side chain added. Each side chain alters the susceptibility of a particular penicillin to inactivating enzymes. MECHANISM OF ACTION All pencillins work by inhibiting bacterial cell wall synthesis, thereby affecting the stability of the cell wall and subsequent bacterial development. The cell wall is made of a peptidoglycan that is synthesized in three stages. MECHANISM OF ACTION

scholarly journals The inhibition of staphylococcal β-lactamase by clavulanic acid

1979 ◽  
Vol 179 (1) ◽  
pp. 67-76 ◽  
Author(s):  
C Reading ◽  
P Hepburn
Keyword(s):  
Enzyme Activity ◽  
Clavulanic Acid ◽  
Cell Extract ◽  
Beta Lactam ◽  
Beta Lactamases ◽  
First Order ◽  
Lactam Ring ◽  
Covalent Intermediate ◽  
Hydrolysis Of ◽  
Inhibited Enzyme

Clavulanic acid inhibited both the extracellular and cell-extract beta-lactamases of the four Staphylococcus aureus strains tested. The inhibition of S. aureus Russell cell-extract enzyme appeared to be active-site-directed and proceeded in a first-order fashion consistent with the formation of a covalent intermediate. Inhibited enzyme free of excess clavulanic acid was shown to regenerate enzyme activity slowly at pH 7.0, but the rate of reactivation increased at acid pH. When the enzyme was incubated with excess clavulanic acid complete inhibition was rapidly obtained, during further incubation clavulanic acid was shown to disappear slowly and complete loss of clavulanic acid from the reaction mixture coincided with the onset of the return of enzyme activity. A reactive enamine resulting from enzymic hydrolysis of the beta-lactam ring of clavulanic acid has been proposed as a possible intermediate in the inhibitory mechanism.

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