- Di-functional magnetic nanoflowers: A highly efficient support for immobilizing penicillin G acylase
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The novel di-functional magnetic nanoflowers (DMNF) which had both epoxy groups and hydrophilic catechol as well as phthaloquinone groups capable of covalently coupling of penicillin G acylase (PGA) were characterized by scanning electron microscopy, transmission electron microscope (TEM), vibrating sample magnetometer, N2 adsorption, and so on. The studies showed that DMNF possessed “hierarchical petal” structure of nanosheets had specific saturation magnetization of 39.7 emu/g and average pore diameter of 25.4 nm as well as specific surface area of 17.28 m2/g. For hydrolysis of penicillin G potassium catalyzed by the PGA immobilized on DMNF with enzyme loading of 106 mg/g-support, its apparent activity reached 2,667 U/g, which benefited from the “hierarchical petal” and large pore structure of the magnetic DMNF leading to high enzyme loading and fast diffusion of substrate molecules to the immobilized PGA to reaction. The apparent activity of the immobilized PGA could keep 2,408 U/g (above 90% of its initial activity) after repeating use for 10 cycles. The magnetic immobilized PGA exhibited excellent operational stability due to covalently coupling of the enzyme molecules between the support by covalent interaction of the amino groups of PGA and the reactive groups of epoxy, catechol, and phthaloquinone groups on DMNF. Furthermore, the PGA displayed good acid and alkaline resistance as well as thermal stability by immobilization using DMNF.
- Zhaoyu, Zheng,Ping, Xue,Keren, Shi,Weiwei, Zhang,Chunmiao, Hu,Peng, Li
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Read Online
- Electrochemical oxidation of amoxicillin on carbon nanotubes and carbon nanotube supported metal modified electrodes
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The electrolysis of amoxicillin (AMX) was carried out on CNT, Pt/CNT and Ru/CNT modified electrodes based on Carbon Toray in 0.1 M NaOH, 0.1 M NaCl and 0.1 M Na2CO3/NaHCO3 buffer (pH 10) media with the aim of studying the significance of two factors, electrode material and pH, on the oxidative degradation and mineralization of AMX. For this purpose, the electrolysis products were identified by HPLC-MS and GC–MS, and quantified by HPLC-UV-RID and IC. The highest carbon mineralization efficiency, corresponding to 30% of the oxidized AMX, was found for Pt/CNT modified electrode in carbonate buffer medium. Regarding to the AMX conversion, the results show that the effect of pH is higher than that of the electrode material. Principal component analysis allowed to determine the experimental parameters vs. product distribution relationship and to elucidate the oxidation pathways for the studied electrodes. The results show that the hydroxylation of the aromatic ring and the nitrogen atom play an important role on the efficient degradation of AMX.
- Ferreira, Marta,Kuzniarska-Biernacka, Iwona,Fonseca, António M.,Neves, Isabel C.,Soares, Olívia S.G.P.,Pereira, Manuel F.R.,Figueiredo, José L.,Parpot, Pier
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p. 322 - 331
(2019/07/10)
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- Development of novel support for penicillin acylase and its application in 6-aminopenicillanic acid production
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There is an ever-increasing demand for the β-lactam bulk intermediate 6-aminopenicillanic acid (6-APA) that has wide applications in the synthesis of newer generations of semisynthetic penicillins. It is commercially synthesized by biocatalytic transformation using penicillin acylase. Since the enzyme is soluble, immobilization on a solid porous support is necessary to make the catalyst recycleable and the process profitable. In this study, we developed a novel support of siliceous foam entrapped in a polymer matrix. Penicillin acylase was covalently immobilized on aminopropyl functionalized mesocellular foam silica (MCF) and was further cross-linked using glutaraldehyde without deactivation and upto 95% efficiency. The resulting biocatalyst had an activity of 1185 IU. mg?1 and demonstrated improved resistance to the substrate and product inhibition. These parameters along with improvement in pH and thermal stability enhanced 6-APA yield by 20% in beads. Intrinsic kinetic parameters were calculated from the developed rate equation to deduce enzyme catalytic mechanism.
- Ayakar, Sonal R.,Yadav, Ganapati D.
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- A PROCESS FOR THE PREPARATION OF AMOXICILLIN TRIHYDRATE
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The invention relates to an in-situ process for the preparation of amoxicillin trihydrate from sugarcane juice without isolation of the intermediates produced during the reaction sequence viz penicillin G and 6-aminopenicillanic acid. The invention provides an in-situ cost effective and environment friendly process in which no separate synthesis of the intermediates, no purification cost and no crystallization cost for the intermediates is required.
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Page/Page column 11; 12
(2014/09/03)
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- Purification of amoxicillin trihydrate by impurity-coformer complexation in solution
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In this work, we demonstrated the purification of amoxicillin trihydrate (AMCT) by the formation of 4-hydroxyphenylglycine (4HPG)-coformer complex in solution. Without advanced knowledge of cocrystal formation of 4HPG, a workflow was established to choose
- Hsi, Kay Huai Ying,Concepcion, Anthony Joseph,Kenny, Meghan,Magzoub, Amna Ahmed,Myerson, Allan S.
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p. 6776 - 6781
(2013/09/02)
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- Amino ester hydrolase from Xanthomonas campestris pv. campestris, ATCC 33913 for enzymatic synthesis of ampicillin
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α-Amino ester hydrolases (AEH) are a small class of proteins, which are highly specific for hydrolysis or synthesis of α-amino containing amides and esters including β-lactam antibiotics such as ampicillin, amoxicillin, and cephalexin. A BLAST search revealed the sequence of a putative glutaryl 7-aminocephalosporanic acid (GL-7-ACA) acylase 93% identical to a known AEH from Xanthomonas citri. The gene, termed gaa, was cloned from the genomic DNA of Xanthomonas campestris pv. campestris sp. strain ATCC 33913 and the corresponding protein was expressed into Escherichia coli. The purified protein was able to perform both hydrolysis and synthesis of a variety of α-amino β-lactam antibiotics including (R)-ampicillin and cephalexin, with optimal ampicillin hydrolytic activity at 25 °C and pH 6.8, with kinetic parameters of kcat of 72.5 s-1 and KM of 1.1 mM. The synthesis parameters α, βo, and γ for ampicillin, determined here first for this class of proteins, are α = 0.25, βo = 42.8 M-1, and γ = 0.23, and demonstrate the excellent synthetic potential of these enzymes. An extensive study of site-directed mutations around the binding pocket of X. campestris pv. campestris AEH strongly suggests that mutation of almost any first-shell amino acid residues around the active site leads to inactive enzyme, including Y82, Y175, D207, D208, W209, Y222, and E309, in addition to those residues forming the catalytic triad, S174, H340, and D307.
- Blum, Janna K.,Bommarius, Andreas S.
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supporting information; scheme or table
p. 21 - 28
(2010/12/19)
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- Process for recovery of 6-aminopenicillanic acid from an aqueous discharge stream
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A process for recovering residual amounts of 6-APA, on the order of 10 g/L or less, from a predominantly aqueous liquor containing phenoxyacetic acid and less than about 2% organic solvents.
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- Chromophoric spin-labeled beta-lactam antibiotics for ENDOR structural characterization of reaction intermediates of class A and class C beta-lactamases.
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The chromophoric spin-label substrate 6-N-[3-(2,2,5,5-tetramethyl-1-oxypyrrolin-3-yl)-propen-2-oyl]penicillanic acid (SLPPEN) was synthesized by acylation of 6-aminopenicillanic acid with the acid chloride of 3-(2,2,5,5-tetramethyl-1-oxypyrrolinyl)-2-propenoic acid and characterized by physical methods. By application of angle-selected electron nuclear double resonance (ENDOR), we have determined the molecular structure of SLPPEN in solution. SLPPEN exhibited UV absorption properties that allowed accurate monitoring of the kinetics of its enzyme-catalyzed hydrolysis. The maximum value of the (substrate-product) difference extinction coefficient was 2824 M(-1) cm(-1) at 275 nm compared to 670 M(-1) cm(-1) at 232 nm for SLPEN [J. Am. Chem. Soc. 117 (1995) 6739]. For SLPPEN, the steady-state kinetic parameters kcat and kcat/KM, determined under initial velocity conditions, were 637 +/- 36 s(-1) and 13.8 +/- 1.4 x 10(6) M(-1) s(-1), respectively, for hydrolysis catalyzed by TEM-1 beta-lactamase of E. coli, and 0.5 +/- 0.04 s(-1) and 3.9 +/- 0.4 x 10(4) M(-1) s(-1) for hydrolysis catalyzed by the beta-lactamase of Enterobacter cloacae P99. We have also observed burst kinetics for the hydrolysis of SLPPEN with P99 beta-lactamase, indicative of formation of an acylenzyme reaction intermediate. In DMSO:H2O (30:70, v:v) cryosolvent mixtures buffered to pH* 7.0, the half-life of the acylenzyme intermediate formed with the P99 enzyme at -5 degrees C was > or = 3 min, suitable for optical characterization. The observation of burst kinetics in the hydrolysis of SLPPEN catalyzed by P99 beta-lactamase suggests that this chromophoric spin-labeled substrate is differentially sensitive to active site interactions underlying the cephalosporinase and penicillinase reactivity of this class C enzyme.
- Mustafi, Devkumar,Hofer, Jennifer E,Huang, Wanzhi,Palzkill, Timothy,Makinen, Marvin W
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p. 1279 - 1289
(2007/10/03)
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- Glutaryl Acylases: One-Reaction Enzymes or Versatile Enantioselective Biocatalysts?
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A significant broad substrate specificity, that crosses over the usual β-lactam derivatives, has been observed with an industrial glutaryl-7-aminocephalosporanic acid acylase (GA). This enzyme possesses significant enantioselective amidase and even esterase activity, with a stereopreference for the S-enantiomer. The easy separation of products from unreacted reagents, possessing different physical-chemical properties, is achieved by solvent extraction, avoiding chromatography or distillation during reaction work-up.
- Raimondi, Stefano,Monti, Daniela,Pagnoni, Ugo Maria,Riva, Sergio
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p. 783 - 789
(2007/10/03)
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- Enzymatic hydrolysis of β-lactam antibiotics at low pH in a two-phase "aqueous solution - Water-immiscible organic solvent" system
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The application of the two-phase "aqueous solution - water-immiscible organic solvent" system is suggested not for effective biocatalytic synthesis, but for hydrolytic purposes. Enzymatic hydrolysis of benzylpenicillin and N-phenylacetamidodesacetoxycepha
- Chilov, Ghermes G.,Svedas, Vytas K.
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p. 699 - 707
(2007/10/03)
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- Bioreaction engineering for improved 6-APA production
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Bioreaction engineering gives tools to improve the production of 6-aminopenicillanic acid by enzyme-catalyzed hydrolysis of penicillin G, using penicillin G amidase (E.C. 3.5.1.11) immobilized on polyacrylamide.The influence of buffer concentration on preventing development of a lower pH at the immobilized enzyme, and application of lower substrate concentrations for reduction of product inhibition are examined.A mathematical model for simulation of the process is also developed.
- Danzig, Joachim,Tischer, Wilhelm,Wandrey, Christian
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- THE USE OF PENICILLIN ACYLASE FOR SELECTIVE N-TERMINAL DEPROTECTION IN PEPTIDE SYNTHESIS
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Penicillin acylase from E. coli (EC 3.5.1.11) accepts a broad range of N-phenylacetyl-dipeptide esters as substrates.The enzyme hydrolyses the N-terminal protecting group selectively at room temp. and pH=8.1 without affecting the peptide- or the ester-bonds.Alternatively methyl-, benzyl-, tert-butyl and allyl esters can be cleaved chemically leaving the phenylacetamido moiety intact.
- Waldmann, Herbert
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p. 1131 - 1134
(2007/10/02)
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- Deacylation of amides
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De-acylation of Penicillins and Cephalosporins to obtain the corresponding 6-aminopenicillanic acid or 7-aminocephalosporanic acid by the imino halide/imino ether process using long chain bases.
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- Process for chemically removing the acyl sidechain from cephalosporins and penicillins
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A process for removing the acyl sidechain from penicillins and cephalosporins which comprises chlorinating the acyl compound and treating the resulting iminochloride with an o-aminothiophenol to obtain the corresponding 6β-aminopenicillin or 7β-aminocephalosporin.
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- β-Lactam antibiotic esterification process using methoxymethyl methane sulfonate
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Disclosed is an improved process for esterifying carboxylic acids, particularly 3-carboxylic acid groups of penicillins and 4-carboxylic acid groups of cephalosporins, to form methoxymethyl esters. Replacement according to the present process of the conventional halomethyl methyl ether esterifying agent with methoxymethyl mesylate avoids the carcinogenicity problem of the prior art reagent while still giving good yields of high quality product.
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- Process for producing 6-aminopenicillanic acid or 7-aminocephalosporanic acid derivatives
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A derivative of 6-aminopenicillanic acid or 7-aminocephalosporanic acid is produced by a process which comprises disulfidizing a 6-thioacylaminopenicillanic acid or 7-thioacylaminocephalosporanic acid compound to obtain a corresponding disulfide compound, and then solvolyzing the disulfide compound. The process is novel and industrially feasible for producing the amino compound, which is not accompanied by "reconversion reaction".
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- Process for production of 6-aminopenicillanic acid or 7-aminocephalosporanic acid derivatives
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A derivative of 6-aminopenicillanic acid or 7-aminocephalosporanic acid is produced by a process which comprises chlorinating or brominating a 6-thioacylaminopenicillanic acid or 7-thioacylaminocephalosporanic acid compound to obtain a corresponding iminothiohalide compound, and then solvolyzing the iminothiohalide compound. The process is novel and industrially feasible for producing the amino compound, which is not accompanied by "reconversion reaction".
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- Novel penicillins and cephalosporins and process for producing the same
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Novel penicillins and cephalosporins and non-toxic salts thereof, which contain a mono- or di-oxo- or thioxo-piperazino(thio)carbonylamino group have been prepared. These compounds are valuable antibacterial compounds for use in mammals including man. A process for the preparation of the compounds has also been discovered.
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- Process for the manufacture of aminoazetidinones
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The present invention relates to a new process for the preparation of 6-aminopenicillanic acid and 7-amino-cephalosporanic acid derivatives by treating the corresponding acylamino derivatives with phosphinic acid chlorides, reacting the mixed acid anhydrides so obtained with agents forming imidohalides, converting the imido halides into iminoethers and hydrolysing them.
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- 1-Oxides of Schiff bases of 6-aminopenicillanic acid
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Compounds containing a cephem nucleus are prepared by heating a 1-oxide of a Schiff base of 6-aminopenicillanic acid. These cephem compounds are useful as intermediates in the preparation of physiologically active cephalosporins.
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- Immobilized microbial cells
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Immobilized microbial cells are prepared by treating microbial cells with a polyfunctional cross-linking reagent and contacting the treated cells in aqueous medium with a water insoluble particulate polymer prepared by polymerizing an ethylenically unsaturated monomer. Alternatively, the treated cells may be bonded to the monomer prior to polymerizing.
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