- On the substrate preference of glutaryl acylases
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The substrate preferences of three acylases - two wild-type enzymes and an evolved variant obtained by directed evolution - which are prototypical enzymes for glutaryl-7-ACA acylase and cephalosporin C acylase subfamilies, have been investigated. A preliminary screening of enzymes' performances on a large set of substrates has been carried out by a colorimetric assay performed in 96-well plates and by a pH-Stat monitoring the hydrolytic activities. Subsequently, kinetic data for selected substrates have been determined, thus elucidating the substrate preference of members of glutaryl-7-ACA acylase vs. cephalosporin C acylase subfamilies. These achievements pave the way to the ability of choosing the best enzyme for the hydrolysis of different compounds of industrial importance.
- Rosini, Elena,Monelli, Claudia Stella,Pollegioni, Loredano,Riva, Sergio,Monti, Daniela
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- PROCESS FOR THE PRODUCTION OF CEPHALOSPORINS
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The present invention relates to a composition comprising ≥85 wt% of an N-deacylated cephalosporin, a process for making the same and the use of said N-deacylated cephalosporin in the preparation of highly pure semi synthetic cephalosporins.
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Page/Page column 10-11
(2012/03/27)
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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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scheme or table
p. 21 - 28
(2010/12/19)
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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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- A facile synthesis of 7-amino-3-desacetoxycephalosporanic acid derivatives by indium-mediated reduction of 3-iodomethylcephems in aqueous media
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An efficient reductive conversion of 3-iodomethylcephalosporin and 3- acetoxymethylcephalosporin derivatives mediated by indium into the corresponding 3-methylcephems and 3-methylenecephams in moderate to good yields has been developed in an aqueous system. 3-Methylenecephams are converted into the corresponding 3-methylcephems under previously reported basic conditions quantitatively. (C) 2000 Elsevier Science Ltd.
- Chae, Hyungsun,Cho, Sangwon,Keum, Gyochang,Kang, Soon Bang,Pae, Ae Nim,Kim, Youseung
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p. 3899 - 3901
(2007/10/03)
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- Process for P-nitrobenzyl ester cleavage in cephalosporin
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A process for converting cephalosporin p-nitrobenzyl ester (Formula I) to the corresponding cephalosporin free acid (Formula II) comprising treating the cephalosporin p-nitrobenzyl ester with a metal selected from the group consisting of iron, magnesium, aluminum, and tin, and with hydrochloric acid in a mixture of water and a water-miscible organic solvent. Preferably, the metal is iron in the form of a fine powder, and the reaction is carried out at a temperature in the range of 30°-50° C.
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- Synthesis of potential impurities of cefalexin and cefradine
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The synthesis of some impurities of the cephalosporin antibiotics cefalexin and cefradine is described. These impurities which may be present in commercial samples are formed during the semi-synthetic preparation of these antibiotics or upon their degradation. The preparation of these compounds enables the validation of selective quantitative analytical methods, such as column liquid chromatography and thin layer chromatography.
- Hendrix,Roets,Bervoets,Thomas,Pijcke,Busson,Janssen,Hoogmartens
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p. 215 - 219
(2007/10/02)
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- Selective deprotective method using palladium-water soluble catalysts
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Allylcarboxy and Allyloxycarbonyl groups can be removed without affecting dimethylallylcarboxy and cinnamylcarboxy groups in the same molecule. using Pd(O) water soluble catalyst prepared in situ, with diethylamine as allyl scavenger. Homogeneous or biphasic media are suitable: the yields of deprotection are quantitative.
- Lemaire-Audoire,Lemaire-Audoire, Sandrine,Savignac,Savignac, Monique,Blart,Blart, Errol,Pourcelot,Pourcelot, Guy,Genet,Genet, Jean Pierre,Bernard,Bernard, Jean-Marie
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p. 8783 - 8786
(2007/10/02)
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- Process for the preparation of 7-amino and 7-substituted amino-desacetoxycephalosporins
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An improved process is disclosed for the preparation of 7-amino and 7-substituted amino-desacetoxycephalosporins in which the corresponding 6-substituted amino penicillin sulphoxide is heated in the presence of an acidic substance which causes expansion of the penam ring in the reactant to the Δ3 cephem ring in the product in the presence of a silicon containing compound. The process comprises adding sulphamide or a silylsulphamide or a silylsulphamoyl to the reaction or utilizing a silylsulphamide or silylsulphamoyl as the silicon containing compound.
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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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- APPLICATION OF ACETOXYMETHYL ESTERS OF PENICILLINS FOR PREPARATION OF 7-AMINO-DESACETOXY-CEPHALOSPORANIC ACID (7-ADCA)
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A simple method of preparing 7-amino-desacetoxy-cephalosporanic acid (7-ADCA) from acetoxymethyl esters of natural penicillins has been described.
- Gruszecki, Wojciech,Gdulewicz-Gruszecka, Maria,Borowski, Edward
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p. 1675 - 1679
(2007/10/02)
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- Process for preparation of penicillin and cephalosporin imino halides
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Penicillin and cephalosporin imino halides are prepared by reacting of 6-acylaminopenicillins or 7-acylamino cephalosporins with a novel chlorinating compound derived from a triaryl phosphite and chlorine or bromine. The imino halide products are intermediates in the preparation of antibiotic compounds.
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- De-esterification process for cephalosporins
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p-Nitrobenzyl esters of cephalosporins are reductively cleaved with zinc and α-hydroxycarboxylic acids, e.g., the p-nitrobenzyl ester of the cephalosporin antibiotic, cephalexin, is reacted in an inert solvent with zinc and mandelic acid to provide the antibiotic, cephalexin, as the free acid in yields greater than 85 percent.
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- Process for the preparation of 7-aminocephalosporanic acids
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7-Aminocephalosporanic acid (7-ACA) and 7-amino-3-methyl-3-cephem-4-carboxylic acid (7-ADCA) are valuable intermediates in the preparation of semi-synthetic cephalosporins. These compounds are commonly prepared by cleaving the amide bond of compounds having the formula SPC1 In which R6 is H or EQU1 R is the side chain of a known penicillin, especially phenoxymethyl or benzyl, and the amino and carboxyl functions are blocked; by A. halogenating the blocked compounds Ia or IIa to produce an imino-halide; B. forming an imino-ether from the imino-halide by treatment with an alcohol; and C. mixing said imino-ether with water or an alcohol to produce 7-aminocephalosporanic acid or 7-amino-3-methyl-3-cephem-4-carboxylic acid. The invention claimed is the use of dicyclohexylamine or diisopropylamine instead of a tertiary amine acid scavenger in step A.
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