penicillin g acylase from e. coli ta1 was immobilized by cross-linked enzyme aggregates (clea), a new method for immobilization. this biocatalyst and commercial immobilized penicillin g acylase (pga-450) were used to study the effect of ph, temperature and substrate concentration on the synthesis of ampicillin from phenyl glycine methyl ester (pgme) and 6-aminopenicillanic acid (6-apa). compare...

Penicillin acylase formation by the hybrid strain Escherichia coli 5K(pHM12) was studied under different culture conditions and reached 200 to 250 mumol of 6-aminopenicillanic acid per min per g of bacteria (wet weight) for penicillin G. The Km of whole-cell acylase was determined with 9 to 11 mM for penicillin G at a pH optimum of 7.8 at 45 degrees C. A competitive product inhibition for pheny...

A homologue of the Escherichia coli penicillin acylase is encoded in the genomes of several thermophiles, including in different Thermus thermophilus strains. Although the natural substrate of this enzyme is not known, this acylase shows a marked preference for penicillin K over penicillin G. Three-dimensional models were created in which the catalytic residues and the substrate binding pocket ...

Penicillin acylase proteins are amidohydrolase enzymes that cleave penicillins at the amide bond connecting the side chain to their beta-lactam nucleus. An unannotated protein from Bacillus subtilis has been expressed in Escherichia coli, purified and confirmed to possess penicillin V acylase activity. The protein was crystallized using the hanging-drop vapour-diffusion method from a solution c...

Residue phenylalanine 71 of the β-chain of penicillin acylase from E. coli is involved in substrate binding and chiral discrimination of its enantiomers. Different amino acid residues have been introduced at position βF71, and the mutants were studied with respect to their enantioselectivity and substrate specificity. Some mutants demonstrated remarkably improved catalytic activity. Moreover, m...

Penicillin G acylase was purified from the cultured filtrate of Arthrobacter viscosus 8895GU and was found to consist of two distinct subunits with apparent molecular weights of 24,000 (alpha) and 60,000 (beta). The partial N-terminal amino acid sequences of the alpha and beta subunits were determined with a protein gas phase sequencer, and a 29-base oligonucleotide corresponding to the partial...

This paper reports the covalent immobilization of penicillin G acylase from E. coli on sepabeads EC-EP, an epoxy-activated polymethacrylic carrier, and describes kinetic properties of the immobilized enzyme. The selected enzyme belongs to a class of biocatalysts whose industrial interest is due to their versatility to mediate hydrolysis of penicillins and semi-synthetic β−lactam antibiotics syn...

Penicillin acylase, an industrially important biocatalyst catalyzes the conversion of penicillins to 6-amino penicillanic acid (6-APA) which is the main precursor for the production of semisynthetic ß-lactam antibiotics. The present work involves the continuous production of 6APA in a packed column reactor by using agarose immobilized penicillin acylase as a block polymer. The strain Escherichi...

The production of penicillin acylase by Escherichia coli Ny.I/3-67 has been increased by phenylacetic acid and phenoxyacetic acid, which themselves strongly inhibit the function of this specific enzyme. Other carbonic acids also increased penicillin acylase production, but to a lesser degree; they also weakly inhibited enzyme function. The production of this enzyme was effectively repressed wit...