Topic
Penicillin amidase
About: Penicillin amidase is a research topic. Over the lifetime, 576 publications have been published within this topic receiving 15563 citations. The topic is also known as: penicillin amidohydrolase & ampicillin acylase.
Papers published on a yearly basis
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TL;DR: The design and characterization of a biocatalyst with whole cells of E. coli containing penicillin acylase activity were carried out and the catalyst was characterized in terms of its kinetic and diffusional properties as a function of particle size, as well as its storage and operational stability.
8 citations
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TL;DR: The extraction of penicillin acylase by reverse micellar solutions of a surfactant was studied and the increase in the specific activity of the final enzyme preparation, after stripping of the organic phase at pH 7.5, in the presence of 1 M KCl, was 8 - fold.
Abstract: The extraction of penicillin acylase by reverse micellar solutions of a surfactant was studied. A 50 mM solution of dioctyl sodium sulphosuccinate in isooctane extracted 46% of the enzyme activity in a crude periplasmic extract of induced cells of E. coli ATCC 9637. The increase in the specific activity of the final enzyme preparation, after stripping of the organic phase at pH 7.5, in the presence of 1 M KCl, was 8 - fold.
8 citations
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TL;DR: In this paper, the substrate specificity of immobilized penicillin-G acylase towards cephalosporin derivatives was studied, where the phenylacetyl meiety can be altered at the @-position with several small substitutes.
8 citations
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TL;DR: When penicillin acylase and beta-lactamase co-existed in the one organism, the respective activities were determined by use of the copper-ascorbate-EDTA fluorescence assay for ampicilloate coupled with a fluorescamine assay for 6-aminopenicillanic acid determinations.
Abstract: Sodium ampicilloate concentrations were estimated fluorimetrically by
heating solutions with ascorbic acid, EDTA and a modified Lowry A reagent
which was prepared by including copper sulfate and potassium sodium
tartrate in 0.5 mol dm
-
3
acetate buffer at pH
4. A concentration range of 0.5–50 µmol
dm
-
3
was used for the estimations. The
reaction was used to estimate β-lactamase activity on ampicillin but
the substrate also showed some fluorescence and a calculation was required
to determine the amount of ampicilloate formed when both substances were
present in the one reaction mixture. The β-lactamase was inhibited by
treatment with trichloroacetic acid so the procedure could be used to
assay the enzyme activity after a fixed time. 6-Aminopenicillanic acid did
not fluoresce on treatment with the modified reagent and organisms which
contained penicillin acylase lowered the amount of ampicillin which could
be converted to ampicilloate. When penicillin acylase and β-lactamase
co-existed in the one organism, the respective activities were determined
by use of the copper–ascorbate–EDTA fluorescence assay for
ampicilloate coupled with a fluorescamine assay for 6-aminopenicillanic
acid determinations. On prolonged incubation, some organisms containing
penicillin acylases lowered the amount of ampicilloate which formed a
fluorescent product. This effect was attributed to deacylation of
ampicilloate by the penicillin acylases.
8 citations
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TL;DR: The three‐dimensional homology model represents a useful and efficient tool for fully exploiting this attractive and efficient biocatalyst, particularly in enantioselective acylations of amines.
Abstract: A three-dimensional model of the relatively unknown penicillin acylase from Alcaligenes faecalis (PA-AF) was built up by means of homology modeling based on three different crystal structures of penicillin acylase from various sources. An in silico selectivity study was performed to compare this homology model to the structure of the Escherichia coli enzyme (PA-EC) in order to find any selectivity differences between the two enzymes. The program GRID was applied in combination with the principal component analysis technique to identify the regions of the active sites where the PAs potentially engage different interactions with ligands. These differences were further analyzed and confirmed by molecular docking simulations. The PA-AF homology model provided the structural basis for the explanation of the different enantioselectivities of the enzymes previously demonstrated experimentally and reported in the literature. Different substrate selectivities were also predicted for PA-AF compared to PA-EC. Since no crystallographic data are available for PA-AF to date, the three-dimensional homology model represents a useful and efficient tool for fully exploiting this attractive and efficient biocatalyst, particularly in enantioselective acylations of amines.
8 citations