Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.1.4 (deaminase)
 5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Septum formation and septum separation have been studied in a chain-forming mutant of Escherichia coli K-12 bearing the envA mutation and its parental strain. In comparison to the wild type, the mutant showed a sixfold reduction in the specific activity of the enzyme, N-acetylmuramyl-L-alanine amidase (EC 3.5.1.28), part of which was associated to the outer membrane. Genetic as well as physiological suppression of chain formation resulted in an increase in amidase activity. The addition of N-acetylmuramyl-L-alanyl-D-glutamyl-meso-diaminopimelic acid to growing wild-type cells and to cells bearing the envA mutation caused an inhibition of cell separation and an increased frequency of visible septa. The kinetics of septum formation and separation was followed in chains by the use of ampicillin and nalidixic acid. The latter drug inhibited initiation of new septa but allowed preformed ones to go to cell separation at a rate corresponding to that of steady-state growing cells. Ampicillin treatment, on the other hand, resulted in a more rapid decrease in the frequency of septa. The disparate effects of ampicillin and nalidixic acid were not explained by a difference in amidase activity but could be due to an inhibitory effect of ampicillin on a septal peptidoglycan fusing activity.
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PMID:Evidence for a role of N-acetylmuramyl-L-alanine amidase in septum separation in Escherichia coli. 6 61

It was shown that serum of albino mice infected with plague microbe cells inactivated benzylpenicillin. Such deacetylating activity reached its peak by the 3rd day and after that decreased reaching by the 5th--7th day the level registered in non-infected animal and being apparently of non-specific character. Ampicillin proved to be 2 times more resistant to the effect of serum acylase as compared to benzylpenicillin. It was supposed that the ability of serum of infected animals to inactivate benzylpenicillin by splitting off phenylace acid was the cause of ineffective treatment of experimental plague of albino mice with comparatively low doses of the drug.
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PMID:[Deacylating activity of sera as a cause for the ineffectiveness of the treatment of experimental plaque in white mice with benzylpenicillin]. 84 16

Ampicillin acylase, which is known to have a novel substrate spectrum, was purified to homogeneity from Pseudomonas melanogenum by the crude extract preparation and chromatography with S-Sepharose, hydroxyapatite, CM-cellulose C-52, and CM-Sepharose. The molecular weight of the native enzyme was calculated to be 146,000 by Protein PAK-300 sw HPLC chromatography. SDS-polyacrylamide gel electrophoresis revealed that the enzyme consisted of two identical subunits with a molecular weight of 72,000. The enzyme was a glycoprotein containing 13% of total carbohydrate, and its isoelectric point was 7.2. The enzyme catalyzed both synthesis and hydrolysis of ampicillin and hydrolysis of the ester bond of phenylglycinemethylester hydrochloride substrate. The substrate specificity showed that the enzyme required a free amino group on the alpha-carbon of the acyl group. Chemical modification by diethylpyrocarbonate or N-bromosuccinimide resulted in time-dependent inactivation of the enzyme, and other results suggest the participation of essential histidine residue(s) in the catalytic activity of ampicillin acylase. Substrates of the enzyme, 6-aminopenicillanic acid and ampicillin, exhibited protective effects against N-bromosuccinimide inactivation, suggesting that the modification occurred near or at the active site.
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PMID:Purification and properties of ampicillin acylase from Pseudomonas melanogenum. 216 18

Ampicillin and cephalexin are beta-lactam antibiotics that are synthesized by the condensation of D-(-)-alpha-aminophenylacetic acid with 6-aminopenicillanic acid or 7-aminodeacetoxycephalosporanic acid, respectively. The rates at which the penicillin amidase of Escherichia coli catalyzes these reactions are too low to be of practical use. The objective of this study was to determine whether it is possible to alter the substrate specificity of penicillin amidase and select enzymes that efficiently hydrolyze substrates with alpha-aminophenylacetyl moieties at low pH, at which the alpha-amino group is nearly completely protonated. In this study, D-(-)-alpha-aminophenylacetyl-(L)-leucine (APAL) was used as a substrate analog of ampicillin and cephalexin. The gene for the penicillin amidase of E. coli ATCC 11105 was cloned and transferred to a leucine auxotroph of E. coli; numerous amidase mutants were selected by their ability to cleave APAL and provide leucine for growth in low-pH medium. The plasmid encoding one of the mutant amidases (pA135) was used to transform naive cells, and transformants that expressed the mutant amidase were shown to grow more rapidly in medium at pH 6.5 containing 0.1 mM APAL as the sole leucine source than did cells with the wild-type amidase. The mutant amidase was purified, and the second-order rate constant (kcat/Km) for APAL hydrolysis at pH 6.5 was found to be 10-fold greater than the rate observed with the wild-type enzyme. The difference between the rates of APAL hydrolysis by the mutant and wild-type amidases increased as the pH of the reactions decreased.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Alteration of the catalytic efficiency of penicillin amidase from Escherichia coli. 269 Jul 34

Ampicillin resistance among strains of Hemophilus is usually due to production of beta-lactamase. This paper reports the isolation of a strain of H. parainfluenzae resistant to ampicillin with no detectable beta-lactamase or amidase activity. The organism, isolated from the blood of a patient who had aortic valve endocarditis, gave a zone diameter consistent with ampicillin sensitivity when tested by disc diffusion in Mueller-Hinton agar supplemented with 1% IsoVitaleX and 1% hemoglobin. Broth dilution testing in Levinthal medium, however, revealed the following minimal inhibitory cencentrations: ampicillin, 32 micrograms/ml; penicillin, 256 micrograms/ml; methicillin, 128 micrograms/ml; carbenicillin, 128 micrograms/ml; and cephalothin and chloramphenicol, 1.0 micrograms/ml. The results of acidimetric, iodometric, and chromogenic cephalosporin methods for detection of beta-lactamase were negative. Beta-lactamase activity could not be demonstrated in cell sonicates or induced by growth of the cells in antibiotic-containing medium. In addition, no extracellular degradation of either ampicillin or penicillin could be demonstrated.
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PMID:Ampicillin resistance in Hemophilus parainfluenzae. 696 94

Affinity ligand (6-Aminopenicillanic acid, Amoxycillin, Ampicillin, Benzylpenicillin and 4-Phenylbutylanzine) of penicillin acylase (EC 3.5.1.11) were attached to hydrophilic gels like Sepharose 4B-CNBr and Minileak 'medium'. Ampicillin and 4-Phenylbutylamine were the affinity ligands that presented the higher concentrations attached to both gels. Penicillin acylase adsorption on these affinity gels was mainly dependent on the activated group of the gel, the affinity ligand attached and the experimental conditions of enzyme adsorption. Under affinity conditions only the ligands Amoxycillin, Ampicillin and 4-Phenylbutylamine, immobilized on Minileak, adsorbed the enzyme from osmotic shock extracts at different pH values. These affinity ligand systems were characterized by low adsorption capacities of penicillin acylase activity (1.2-2.1 IU mL-1 gel) and specific activity (1.5-2.9 IU mg-1 prot). Under pseudo-affinity conditions all the ligands attached both activated to gels (Sepharose 4B-CNBr and Minileak) adsorbed the enzyme. The affinity gels were characterized by higher values of adsorption capacity (3.7 and 55.6 IU mL-1 gel) and adsorbed specific activity (2.0 and 6.1 IU mg-1 prot) than those observed under affinity conditions. The space arm of Minileak gel, shown to be fundamental to enzyme adsorption under affinity conditions, preferentially adsorbed proteins in relation to the enzyme under pseudo-affinity conditions. However, this effect was partially minimized when the gel was derivatized by the affinity ligands at concentrations higher than 6 mumol mL-1 gel. Ampicillin was the affinity ligand that presented the best results for specific adsorption of penicillin acylase under affinity and pseudo-affinity adsorption processes. The Sepharose 4B-CNBr derivatized gel also presented a good adsorption capacity of enzyme activity (26.8 IU mL-1 gel) under pseudo-affinity adsorption processes.
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PMID:Evaluation of affinity and pseudo-affinity adsorption processes for penicillin acylase purification. 921 Mar 49

The influence of ampicillin and chloramphenicol administered intraperitoneally singly or in combination on the protein content and the activities of hepatic esterase and amidase have been investigated in rats. The results have been compared to the effects of phenobarbitone (inducer) and p-nitrophenyl-phosphate (inhibitor) of hepatic hydrolases. Ampicillin pretreatment reduced protein level and amidase activity by 3.5% each but caused a significant increase (8.1%) in total esterase activity compared to controls. Chloramphenicol treatment caused an overall decrease in protein level, esterase and amidase activities respectively by 11%, 11%, and 35% over controls. Combined administration of both drugs resulted in a decrease in protein, esterase and amidase activities by 11.5%, 12.5%, and 41.2% respectively, thus mimicking the effects obtained with chloramphenicol alone. The changes induced by administration of the drugs particularly in combination on the constituent enzymes of rat hepatic hydrolases may affect the ability of the body to deal with exposure to environmental chemicals if extrapolated to man.
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PMID:Chloramphenicol and ampicillin-induced changes in rat hepatic esterase and amidase activities. 1088 7