Penicillin G Acylase
Mostrando 13-24 de 33 artigos, teses e dissertações.
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13. Separação de ampicilina produzida enzimaticamente por reação entre éster metílico de fenilglicina e ácido 6-aminopenicilânico.
The separation/concentration process of the products obtained from the enzymatic synthesis of ampicillin (AMP) catalyzed by immobilized penicillin G acylase was the focus of this Thesis. Hydrophobic resin adsorption and isoelectric precipitation were the processes herein evaluated. The antibiotic was produced in the solid phase, from 6-aminopenicillanic acid
Publicado em: 2003
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14. A simplified kinetic model for the side reactions occurring during the enzymatic synthesis of ampicillin
This work presents a kinetic study of the side reactions of the ampicillin enzymatic synthesis, from phenylglycine methyl ester and 6-aminopenicillanic acid using penicillin G acylase immobilized on agarose. A Michaelis-Menten model with competitive inhibition was fitted to initial rates of ester and antibiotic hydrolysis, at pH 6.5 and 25ºC. Inherent kinet
Brazilian Journal of Chemical Engineering. Publicado em: 2000-12
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15. Expression of the Arthrobacter viscosus penicillin G acylase gene in Escherichia coli and Bacillus subtilis.
The penicillin G acylase gene cloned from Arthrobacter viscosus 8895GU was subcloned into vectors, and the recombinant plasmids were transferred into Escherichia coli or Bacillus subtilis. Both E. coli and B. subtilis transformants expressed the A. viscosus penicillin G acylase. The enzyme activity was found in the intracellular portion of the E. coli transf
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16. Molecular cloning and analysis of the gene encoding the thermostable penicillin G acylase from Alcaligenes faecalis.
Alcaligenes faecalis penicillin G acylase is more stable than the Escherichia coli enzyme. The activity of the A. faecalis enzyme was not affected by incubation at 50 degrees C for 20 min, whereas more than 50% of the E. coli enzyme was irreversibly inactivated by the same treatment. To study the molecular basis of this higher stability, the A. faecalis enzy
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17. Effects of site-directed mutations on processing and activities of penicillin G acylase from Escherichia coli ATCC 11105.
Penicillin G acylase from Escherichia coli ATCC 11105 is synthesized from its precursor polypeptide into a catalytically active heterodimer via a complex posttranslational processing pathway. Substitutions in the pair of aminoacyl residues at the cleavage site for processing the small and large subunits were made. Their processing phenotypes and penicillin G
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18. Molecular cloning of the penicillin G acylase gene from Arthrobacter viscosus.
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 oligonu
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19. Repression of penicillin G acylase of Proteus rettgeri by tricarboxylic acid cycle intermediates.
The regulation of the penicillin acylase in proteus rettgeri ATCC 31052 was compared with that of the enzyme in Escherichia coli ATCC 9637. Unlike the E. coli acylase, the P. rettgeri enzyme was not induced by phenylacetic acid, nor was it subject to catabolite repression by glucose. The P. rettgeri acylase appears to be expressed constitutively but is subje
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20. Penicillin Acylase Activity of Penicillium chrysogenum1
The penicillin acylase activity of Penicillium chrysogenum was studied. Washed mycelial suspensions of a high penicillin-producing and a nonproducing strain were found to be similar in respect to relative acylase activity on benzylpenicillin, 2-pentenylpenicillin, heptylpenicillin, and phenoxymethylpenicillin. The relative rates for both strains, as determin
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21. Role of protein subunits in Proteus rettgeri penicillin G acylase.
Penicillin G acylase from Proteus rettgeri is an 80,000- to 90,000-dalton enzyme composed of two nonidentical subunits. Both subunits were required for enzymatic activity. The 65,000-dalton beta subunit contained a phenylmethylsulfonyl fluoride-sensitive residue required for enzymatic activity, and the 24,500-dalton alpha subunit contained the domain that im
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22. Penicillin acylase from the hybrid strains Escherichia coli 5K(pHM12): enzyme formation and hydrolysis of beta-lactam antibiotics with whole cells.
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 com
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23. Expression and regulation of the penicillin G acylase gene from Proteus rettgeri cloned in Escherichia coli.
The penicillin G acylase genes from the Proteus rettgeri wild type and from a hyperproducing mutant which is resistant to succinate repression were cloned in Escherichia coli K-12. Expression of both wild-type and mutant P. rettgeri acylase genes in E. coli K-12 was independent of orientation in the cloning vehicle and apparently resulted from recognition in
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24. Characterization of an Escherichia coli aromatic hydroxylase with a broad substrate range.
The hpaB gene encoding an aromatic hydroxylase of Escherichia coli ATCC 11105, a penicillin G acylase-producing strain, has been cloned and expressed in E. coli K-12. This gene was located near the pacA gene coding for penicillin G acylase. The hydroxylase has a molecular mass of 59,000 Da, uses NADH as a cosubstrate, and was tentatively classified as a 4-hy