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

Highly purified penicillin G acylase from a mutant derivative of Escherichia coli ATCC 11105 was immobilized on oxirane-acrylic beads by covalent binding via oxirane groups. The highest specific activity, (322 U g-1 dry matrix at 40 degrees C and at pH 8.0) was obtained by using an enzyme solution having 13.8 U mg-1 specific activity and 72.73 mg total protein. The efficiency of immobilization was 95.8%. Kinetic parameters of immobilized penicillin G acylase were determined at the same pH and temperature by a preparation having 8.1 mg bound protein. The Km value and substrate inhibition constant of the enzyme were found to be 11.36 mmol dm-3 and 680 mmol dm-3 penicillin G respectively. Phenylacetic acid and 6-aminopenicillanic acid were estimated as the competitive and non-competitive inhibitors of the enzyme and their inhibition constants were found to be 90 mmol dm-3 phenylacetic acid and 76.1 mmol dm-3 for 6-aminopenicillanic acid. The activation energy of the hydrolytic reaction was calculated to be 7.75 kcal mol-1. The immobilized enzyme showed highest activity at pH 8.0 and at 55 degrees C. The enzyme was stable when incubated at 4 degrees C for one day at a pH range of 5.0 to 9.0. Thermal stability (over 30 min) was observed up to 40 degrees C but decreased at higher temperatures and was almost absent at 60 degrees C. A 95% conversion rate was observed at 28 degrees C and at 40 degrees C with 60 and 30 min operation times respectively. Operational stability of the enzyme was improved further with dithiothreitol treatment. Activity loss was around 5% following 20 cycles of repeated use of the enzyme at 40 degrees C. No significant loss of activity was observed at 28 degrees C when the enzyme was used for 20 cycles. 6-Aminopenicillanic acid in the reaction mixture was observed to be stable during conversion reactions which were carried out at both temperatures.
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PMID:Kinetic investigation of penicillin G acylase from a mutant strain of Escherichia coli ATCC 11105 immobilized on oxirane-acrylic beads. 136 8

Isolation and characterization of a beta-lactamase (EC 3.5.2.6)-free, penicillin amidase (penicillin amidohydrolase, EC 3.5.1. 11)-producing organism is reported. The test strain was isolated by an enrichment technique with a substrate other than penicillins. The isolated strain belongs to the genus Alcaligenes. Phenylacetic acid was found to be the inducer of penicillin amidase. The amidase has a broad substrate spectrum. It is very active against penicillin G and semisynthetic cephalosporins, whereas penicillin V and semisynthetic penicillins acted moderately as a substrate. Immobilized cells of Alcaligenes sp. were shown to act as a reversible enzyme.
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PMID:Beta-lactamase-free penicillin amidase from Alcaligenes sp.: isolation strategy, strain characteristics, and enzyme immobilization. 1048 31

A mutant strain of E. coli EP1 harbouring pGL-5 was employed to develop a process for producing penicillin G acylase (PGA). In comparison with different carbon sources in the medium, it was found that the specific levels of PGA activity obtained in the glucose medium were the lowest. which was likely due to catabolic repression. Phenylacetic acid (PAA) was previously reported to be an regulatory inducer for PGA production, whereas in this study, the addition of PAA repressed both cell growth and enzyme expression. In a fed-batch culture, the increase of specific PGA activity followed the pattern of the cell concentration during the early to middle cell growth phase. With application of pure oxygen aeration and an appropriate medium design, the cell concentration reached 162 (g wet weight/l), which was 2.4 times higher compared to that of the original operation, and a specific PGA activity of 37 (IU/g wet weight) was achieved after 12 h of cultivation.
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PMID:Cultivation of recombinant Escherichia coli to achieve high cell density with a high level of penicillin G acylase activity. 1108 67