Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Penicillin acylase from E. coli is able to catalyze both the introduction and the removal of the phenylacetyl group. We have established that phenylacetyl derivatives of amino acids and peptides can be used in protease-catalyzed peptide synthesis. Here the synthesis of leucine-enkephalin using enzymes for N-terminal amino group protection, peptide bond formation and deprotection is described.
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PMID:Penicillin acylase-catalyzed protection and deprotection of amino groups as a promising approach in enzymatic peptide synthesis. 187 33

A major aflatoxin G1 (AFG1)-albumin adduct has been identified and characterized in rats following exposure to AFG1. The product isolated from a Pronase digest of in vivo-modified albumin was identical by chromatographic retention time to the synthetic product obtained by the acylase-catalysed deacetylation product of N alpha-acetyl-L-lysine with 8,9-dihydro-8,9-dibromo-AFG1. The in vitro product, AFG1-lysine, was characterized by UV, fluorescence, 1H- and 13C-NMR spectroscopy and fast atom bombardment MS. A competitive enzyme-linked immunoassay for this adduct was established using polyclonal antibodies to AFB1 and this was used together with an HPLC-fluorescence technique to quantitate the in vivo formation of AFG1-albumin adducts in comparison to AFB1. A linear dose-response relationship was observed in rats following single exposures to 0.1-3 mg AFG1/kg body wt. The levels of AFG1-albumin adducts were determined to be 5.7- and 2.8-fold lower than with equivalent doses of AFB1 as determined by immunoassay and HPLC fluorescence respectively. The lower binding of AFG1 and the lower levels in the human food supply compared to AFB1 suggest that the newly identified adduct could be added as an internal standard for methods using the measurement of aflatoxin-albumin adducts to quantitate human exposure to aflatoxin.
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PMID:Identification of an aflatoxin G1-serum albumin adduct and its relevance to the measurement of human exposure to aflatoxins. 189 57

The technique of cassette and site-specific mutagenesis were used to study the role of residue No. 177 in penicillin G acylase (PGA, EC 3.5.1.11). Ser is conserved at residue No. 177 in all penicillin binding proteins. We got a series of mutants in which the amino acid at residue No. 177 was replaced by other amino acids through the site-specific and cassette mutagenesis, and we characterized the mutants by colony hybridization, NIPAB paper test and DNA sequence analysis. These mutants all show no activity of enzyme, even if the Ser residue was replaced by Thr, Gly and Ala respectively. The results show that Ser residue may be essential for substrate-binding or catalysis of PGA.
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PMID:[Effect of mutagenesis at Ser 177 residue in penicillin G acylase on activity of the enzyme]. 190 33

A series of water-soluble disubstituted carbodiimides of different structure was tested for enzyme immobilization. In the experiments, a polyacrylamide-type bead polymer possessing carboxylic functional groups was used as support. The enzymes immobilized were aminoacylase (N-acylamino acid amidohydrolase; EC 3.5.1.14), arginase (L-arginine amidinohydrolase; EC 3.5.3.1), cyclodextrin glycosyltransferase (alpha-1,4-glucan 4-glycosyltransferase, cyclizing; EC 3.2.1.19), glucoamylase (1,4-alpha-D-glucan glycohydrolase, EC 3.2.1.3), and carboxypeptidase B (peptidyl-L-lysine [L-arginine] hydrolase; EC 3.4.17.2). It was found that the degree of immobilization strongly depended on the structure of carbodiimide used.
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PMID:Effects of carbodiimide structure on the immobilization of enzymes. 195 34

Penicillin G acylase was immobilized on numerous cation exchange resins and hydrophobic adsorbents. Amberlite XAD-7 was the matrix of choice among the matrices studied for the immobilization of enzyme. Binding of 96.8% and expression of 82.6% of the penicillin G acylase was achieved on XAD-7. Penicillin G acylase immobilised on XAD-7 was used for 80 cycles for the production of 6-PA in a stirred tank reactor.
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PMID:Immobilization of penicillin G acylase onto ion exchange and hydrophobic resins. 196 86

Cephalosporin C acylase activity was studied using fluorescamine determination of free--NH2 groups produced in the deacylation of cephalosporin C by the enzyme. Fourteen fungi from different genera were studied and low extracellular cephalosporin C acylase activity was found in the genera Aspergillus, Fusarium and Penicillium. Forty one fungi of these genera were checked but not all presented acylase activity. The enzyme was generally found to be an extracellular enzyme and during the process of autolysis its activity increased with incubation time and with increasing pH of the medium. In no case was beta-lactamase activity detected. Penicillium rugulosum and Penicillium griseofulvum were identified as good cephalosporin C acylase producers. Deacetyl esterase activity was also detected in these fungi.
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PMID:Cephalosporin C acylase in the autolysis of filamentous fungi. 197 99

An 87% identity has been found between the reported cDNA sequence that encodes acylpeptide hydrolase (EC 3.4.19.1) [Mitta, M., Asada, K., Uchimura, Y., Kimizuka, F., Kato, I., Sakiyama, F. & Tsunasawa, S. (1989) J. Biochem. 106, 548-551] and a cDNA transcribed from a locus (DNF15S2) on the short arm of human chromosome 3, reported by Naylor et al. [Naylor, S.L., Marshall, A., Hensel, C., Martinez, P.F., Holley, B. & Sakaguchi, A.Y. (1989) Genomics 4, 355-361]; the DNF15S2 locus suffers deletions in small cell lung carcinoma associated with a reduction or loss of acylase activity (EC 3.5.1.14). Acylpeptide hydrolase catalyzes the hydrolysis of the terminal acetylated amino acid preferentially from small acetylated peptides. The acetylamino acid formed by acylpeptide hydrolase is further processed to acetate and a free amino acid by an acylase. The substrates for the acylpeptide hydrolase and the acylase behave in a reciprocal manner since acylpeptide hydrolase binds but does not process acetylamino acids and the acylase binds acetylpeptides but does not hydrolyze them; however, the two enzymes share the same specificity for the acyl group. These findings indicate some common functional features in the protein structures of these two enzymes. Since the gene coding for acylpeptide hydrolase is within the same region of human chromosome 3 (3p21) that codes for the acylase and deletions at this locus are also associated with a decrease in acylase activity, there is a close genetic relationship between the two enzymes. There could also be a relationship between the expression of these two enzymes and acetylated peptide growth factors in some carcinomas.
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PMID:Genetic relationship between acylpeptide hydrolase and acylase, two hydrolytic enzymes with similar binding but different catalytic specificities. 200 56

The expression of penicillin G acylase (PGA) gene is sensitive to temperature. Cells of E. coli DH 5 alpha harboring a plasmid pWGA carrying a gene for PGA produce active PGA at low level at 37 degrees C, but can synthesize significant amount of the enzyme below 30 degrees C. Active PGA is formed from a 94 KD precursor processed through remove of a signal peptide and a spacer peptide to yield an enzyme that contain a 23 KD (alpha) and 65 KD (beta) subunit. This paper reported the effect of temperature on transcription, translation, and post-translational processing of PGA gene expression. We detected the transcription of PGA gene by Northern blot, and found the amount of PGA mRNA at 37 degrees C much more than that 30 degrees C when the cells of DH 5 alpha (pWGA) were cultured. It is evident that the precursor processing step(s) is sensitive to temperature.
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PMID:[Effect of temperature on the expression of penicillin G acylase gene at the level of post-translational processing]. 203 12

We have developed a strategy for immobilization-stabilization of penicillin G acylase from E. coli, PGA, by multipoint covalent attachment to agarose (aldehyde) gels. We hve studied the role of three main variables that control the intensity of these enzyme-support multiinteraction processes: 1. surface density of aldehyde groups in the activated support; 2. temperature; and 3. contact-time between the immobilized enzyme and the activated support prior to borohydride reduction of the derivatives. Different combinations of these three variables have been tested to prepare a number of PGA-agarose derivatives. All these derivatives preserve 100% of catalytic activity corresponding to the soluble enzyme that has been immobilized but they show very different stability. The less stable derivative has exactly the same thermal stability of soluble penicillin G acylase and the most stable one is approximately 1,400 fold more stable. A similar increase in the stability of the enzyme against the deleterious effect of organic solvents was also observed. On the other hand, the agarose aldehyde gels present a very great capacity to immobilize enzymes through multipoint covalent attachment. In this way, we have been able to prepare very active and very stable PGA derivatives containing up to 200 International Units of catalytic activity per mL. of derivative with 100% yields in the overall immobilization procedure.
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PMID:Immobilization-stabilization of penicillin G acylase from Escherichia coli. 209 28

Penicillin acylase (EC 3.5.1.11) from E. coli, both in solution and immobilized on solid supports, has been commercially exploited for the large scale production of 6-aminopenicillanic acid (6-APA), which is an important intermediate for the manufacturing of semisynthetic penicillins. In this paper a very simple procedure of penicillin acylase purification is reported, which employs only one affinity chromatographic step (Sepharose-phenylacetic column). The enzyme was obtained at a high degree of purity and could be used for immobilization on partially hydrolyzed and activated nylon. Since the support is chemically inert and mechanically stable the catalyst can be used several times without any significant loss of activity, making the process of great commercial importance.
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PMID:E. coli penicillin acylase: purification by affinity chromatography and covalent binding to nylon. 213 95


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