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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.


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Journal ArticleDOI
TL;DR: Molar yields about 60% compare favorably with values reported for the kinetically and thermodynamically controlled synthesis of ampicillin and other derived penicillins, and organic cosolvents can be a suitable reaction media for synthesis.
Abstract: Immobilized penicillin acylase is a moderately priced versatile enzyme, that is able to catalyze the synthesis of derived penicillins and cephalosporins from the corresponding β-lactam nuclei and proper side-chain precursors. Kinetically controlled synthesis is a better strategy when product yield is a key issue. Yield should increase at reduced water activity by depressing the competing hydrolytic reactions in favor of synthesis; therefore, organic cosolvents can be a suitable reaction media for synthesis. Using response surface methodology and product yield as objective function, temperature and pH were optimized in the kinetically controlled synthesis of ampicillin using previously screened cosolvents and reaction conditions. Optimum pH was 6.0 for ethylene glycol (EG) and glycerol (GL) and 6.6 for 1–2 propanediol (PD); optimum temperature was 30°C for GL and for EG and PD was in the lower extreme of the range studied, optimum lying below 26°C. Maximum molar yields predicted by the model were 58,51, and 46% for EG, GL, and PD, respectively, which were experimentally validated. Highest yield in aqueous buffer was always <40%. Molar yields about 60% compare favorably with values reported for the kinetically and thermodynamically controlled synthesis of ampicillin and other derived penicillins.

37 citations

Journal ArticleDOI
TL;DR: The high-expression system developed using the high PGA-producing strain Escherichia coli RE3 as a host and a recombinant plasmid pKA18 which was constructed by cloning the chromosomal pga gene coding for PGA in the strain RE3 on multicopy vector pK19 led to an increase in the specific activity of PGA.

37 citations

Journal ArticleDOI
TL;DR: The present support could be a good candidate for the immobilization of industrial enzymes rich in amino groups, especially the thermophilic ones.
Abstract: κ-Carrageenan hydrogel crosslinked with protonated polyethyleneimine (PEI+) and glutaraldehyde (GA) was prepared and evaluated as a novel biocatalytic support for covalent immobilization of penicillin G acylase (PGA). The method of modification of the carrageenan biopolymer is clearly illustrated using a schematic diagram and was verified by FTIR, elemental analysis, DSC, and INSTRON using the compression mode. Results showed that the gels' mechanical strength was greatly enhanced from 3.9 kg/cm2 to 16.8 kg/cm2 with an outstanding improvement in the gels thermal stability. It was proven that, the control gels were completely dissolved at 35°C, whereas the modified gels remained intact at 90°C. The DSC thermogram revealed a shift in the endothermic band of water from 62 to 93°C showing more gel-crosslinking. FTIR revealed the presence of the new functionality, aldehydic carbonyl group, at 1710 cm−1 for covalent PGA immobilization. PGA was successfully immobilized as a model industrial enzyme retaining 71% of its activity. The enzyme loading increased from 2.2 U/g (control gel) to 10 U/g using the covalent technique. The operational stability showed no loss of activity after 20 cycles. The present support could be a good candidate for the immobilization of industrial enzymes rich in amino groups, especially the thermophilic ones. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

37 citations

Journal ArticleDOI
TL;DR: Proteus rettgeri and Escherichia coli W were shown to express structurally different penicillin G acylases that appeared to have evolved in parallel since each acylase attained similar new substrate specificities when the organisms were subjected to identical selection pressure.
Abstract: Proteus rettgeri and Escherichia coli W were shown to express structurally different penicillin G acylases. The enzymes had similar substrate specificity but differed in molecular weight, isoelectric point, and electrophoretic mobility in polyacrylamide gels and did not antigenically cross-react. When the organisms were subjected to environmental conditions which made expression of this enzyme essential for growth, spontaneous mutants were isolated that used different amides as the only source of nitrogen. These mutants acquired the ability to use amides for growth by deregulating the penicillin G acylase and by their evolution to novel substrate specificities. The enzymes expressed by mutants isolated from each genus appeared to have evolved in parallel since each acylase attained similar new substrate specificities when the organisms were subjected to identical selection pressure.

37 citations

Journal ArticleDOI
TL;DR: Penicillin amidase has been immobilised by covalent binding to DEAE-cellulose using 2-amino-4,6-dichloro-s-triazine and there was no evidence of diffusional limitation of the reaction rate.

37 citations

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20234
20222
20183
20175
20165
20153