- Reshaping the active pocket of esterase Est816 for resolution of economically important racemates
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Bacterial esterases are potential biocatalysts for the production of optically pure compounds. However, the substrate promiscuity and chiral selectivity of esterases usually have a negative correlation, which limits their commercial value. Herein, an efficient and versatile esterase (Est816) was identified as a promising catalyst for the hydrolysis of a wide range of economically important substrates with low enantioselectivity. We rationally designed several variants with up to 11-fold increased catalytic efficiency towards ethyl 2-arylpropionates, mostly retaining the initial substrate scope and enantioselectivity. These variants provided a dramatic increase in efficiency for biocatalytic applications. Based on the best variant Est816-M1, several variants with higher or inverted enantioselectivity were designed through careful analysis of the structural information and molecular docking. Two stereoselectively complementary mutants, Est816-M3 and Est816-M4, successfully overcame and even reversed the low enantioselectivity, and several 2-arylpropionic acid derivatives with highEvalues were obtained. Our results offer potential industrial biocatalysts for the preparation of structurally diverse chiral carboxylic acids and further lay the foundation for improving the catalytic efficiency and enantioselectivity of esterases.
- Liu, Xiaolong,Zhao, Meng,Fan, Xinjiong,Fu, Yao
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p. 6126 - 6133
(2021/09/28)
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- Lipase-Catalyzed Production of (S)-Carprofen Enhanced by Hydroxyethyl-β-cyclodextrins: Experiment and Optimization
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Stereoselective resolution of (R,S)-carprofen methyl ester (CPOMe) by lipase-catalyzed hydrolysis to (S)-carprofen (CP) was investigated in an aqueous medium. With the highest catalytic activity, Candida antarctica Lipase A (CALA) was selected as catalyst compared with eight other lipases. Hydroxyethyl-β-cyclodextrin (HE-β-CD) was added to enhance the solubility of (R,S)-CPOMe, which significantly raised the conversion of substrate from 11.12% to 30.84%. Response surface methodology (RSM) was adopted to evaluate the influence of factors on the substrate conversion (c) and enantiomeric excess of product (eep), such as pH, concentrations of enzyme and HE-β-CD, temperature, substrate loading, and reaction time. The optimal conditions were obtained, including pH 6.0, 40 mg/mL CALA, 0.05 mmol substrate, 35 mmol/L HE-β-CD, agitation speed of 600 rpm, temperature of 76 °C, and reaction time of 30 h. Under the above conditions, (S)-CP as the desired product was obtained with an enantiomeric excess of 96.24% and overall conversion of 46.07%.
- Yuan, Xin,Liu, Guangyong,Zhang, Panliang,Xu, Weifeng,Tang, Kewen
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p. 891 - 899
(2019/05/01)
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- Diquats with Robust Chirality: Facile Resolution, Synthesis of Chiral Dyes, and Application as Selectors in Chiral Analysis
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Diquats with extremely high racemization barriers with ΔG≠theor of 233 kJ mol?1 at 180 °C are described. Reported configurational robustness is due to a combination of two structural features: the rigid o-xylylene tether connecting the nitrogen atoms and the presence of two substituents in the bay region of the bipyridinium scaffold. The straightforward synthesis of diquats, plus facile resolution and derivatization make them attractive for chiral application studies. This is demonstrated by: 1) synthesis of the first non-racemic diquat dyes with pronounced chiroptical properties, and 2) capability of diquats to interact stereospecifically with chiral molecules. This suggests potential for diquat derivatives to be used as chiral selectors in separation methods.
- Talele, Harish R.,Koval, Du?an,Severa, Luká?,Reyes-Gutiérrez, Paul E.,Císa?ová, Ivana,Sázelová, Petra,?aman, David,Bednárová, Lucie,Ka?i?ka, Václav,Teply, Filip
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supporting information
p. 7601 - 7604
(2018/06/11)
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- Enantioselective potential of polysaccharide-based chiral stationary phases in supercritical fluid chromatography
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The enantioselective potential of two polysaccharide-based chiral stationary phases for analysis of chiral structurally diverse biologically active compounds was evaluated in supercritical fluid chromatography using a set of 52 analytes. The chiral selectors immobilized on 2.5?μm silica particles were tris-(3,5-dimethylphenylcarmabate) derivatives of cellulose or amylose. The influence of the polysaccharide backbone, different organic modifiers, and different mobile phase additives on retention and enantioseparation was monitored. Conditions for fast baseline enantioseparation were found for the majority of the compounds. The success rate of baseline and partial enantioseparation with cellulose-based chiral stationary phase was 51.9% and 15.4%, respectively. Using amylose-based chiral stationary phase we obtained 76.9% of baseline enantioseparations and 9.6% of partial enantioseparations of the tested compounds. The best results on cellulose-based chiral stationary phase were achieved particularly with propane-2-ol and a mixture of isopropylamine and trifluoroacetic acid as organic modifier and additive to CO2, respectively. Methanol and basic additive isopropylamine were preferred on amylose-based chiral stationary phase. The complementary enantioselectivity of the cellulose- and amylose-based chiral stationary phases allows separation of the majority of the tested structurally different compounds. Separation systems were found to be directly applicable for analyses of biologically active compounds of interest.
- Kucerova, Gabriela,Kalikova, Kveta,Tesarova, Eva
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supporting information
p. 239 - 246
(2017/05/29)
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- Reversed-phase high-performance liquid chromatographic separation of some 2-arylpropionic acids using vancomycin as chiral stationary phase
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Abstract A rapid, sensitive and reproducible HPLC method has been developed for enantioseparation of six non-steroidal anti-inflammatory drugs, which are acidic compounds: carprofen, fenoprofen, flurbiprofen, ibuprofen, indoprofen and ketoprofen. The effects of the mobile phase composition on retention times and resolutions of the analytes were studied. A column based on vancomycin immobilized by reductive amination to aldehyde functionalised silica was prepared in house and used. The prepared sorbent shows a great stability and selectivity over a range of pH (4-6), and the separation was carried out using the mobile phase composed of a mixture of 40% of methanol in ammonium nitrate buffer (50 mM) at pH 5.0. Another mobile phase consisted of 50% of methanol in phosphate buffer (5A mM) at pH 5.0 was also prepared and tested. The two mobile phases are the optimum conditions obtained. All experiments were conducted at flow rate 0.6 ml/min, using a UV detector wavelength at λ = 254 nm.
- Bouchair, Nabila,Righezza, Michel,Hamdi, Abderrezak
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p. 921 - 928
(2015/05/05)
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- Conventional chiralpak ID vs. capillary chiralpak ID-3 amylose tris-(3-chlorophenylcarbamate)-based chiral stationary phase columns for the enantioselective HPLC separation of pharmaceutical racemates
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A comparative enantioselective analysis using immobilized amylose tris-(3-chlorophenylcarbamate) as chiral stationary phase in conventional high-performance liquid chromatography (HPLC) with Chiralpak ID (4.6mm ID×250mm, 5μm silica gel) and micro-HPLC with Chiralpak ID-3 (0.30mm ID×150mm, 3μm silica gel) was conducted. Pharmaceutical racemates of 12 pharmacological classes, namely, α- and β-blockers, anti-inflammatory drugs, antifungal drugs, dopamine antagonists, norepinephrine-dopamine reuptake inhibitors, catecholamines, sedative hypnotics, diuretics, antihistaminics, anticancer drugs, and antiarrhythmic drugs were screened under normal phase conditions. The effect of an organic modifier on the analyte retentions and enantiomer recognition was investigated. Baseline separation was achieved for 1-acenaphthenol, carprofen, celiprolol, cizolirtine carbinol, miconazole, tebuconazole, 4-hydroxy-3-methoxymandelic acid, 1-indanol, 1-(2-chlorophenyl)ethanol, 1-phenyl-2-propanol, flavanone, 6-hydroxyflavanone, 4-bromogluthethimide, and pentobarbital on the 4.6mm ID packed with a 5μm silica column using conventional HPLC. Nonetheless, baseline separation was achieved for aminoglutethimide, naftopidil, and thalidomide on the 0.3mm ID packed with a 3μm silica capillary column. Chirality 26:677-682, 2014.
- Ahmed, Marwa,Gwairgi, Marina,Ghanem, Ashraf
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p. 677 - 682
(2015/03/31)
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- Identification and characterization of carprofen as a multitarget fatty acid amide hydrolase/cyclooxygenase inhibitor
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Pain and inflammation are major therapeutic areas for drug discovery. Current drugs for these pathologies have limited efficacy, however, and often cause a number of unwanted side effects. In the present study, we identify the nonsteroidal anti-inflammatory drug carprofen as a multitarget-directed ligand that simultaneously inhibits cyclooxygenase-1 (COX-1), COX-2, and fatty acid amide hydrolase (FAAH). Additionally, we synthesized and tested several derivatives of carprofen, sharing this multitarget activity. This may result in improved analgesic efficacy and reduced side effects (Naidu et al. J. Pharmacol. Exp. Ther.2009, 329, 48-56; Fowler, C. J.; et al. J. Enzyme Inhib. Med. Chem.2012, in press; Sasso et al. Pharmacol. Res.2012, 65, 553). The new compounds are among the most potent multitarget FAAH/COX inhibitors reported so far in the literature and thus may represent promising starting points for the discovery of new analgesic and anti-inflammatory drugs.
- Favia, Angelo D.,Habrant, Damien,Scarpelli, Rita,Migliore, Marco,Albani, Clara,Bertozzi, Sine Mandrup,Dionisi, Mauro,Tarozzo, Glauco,Piomelli, Daniele,Cavalli, Andrea,De Vivo, Marco
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p. 8807 - 8826,20
(2020/09/16)
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- COX-2 selective carprofen for treating pain and inflammation in dogs
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Treating or preventing inflammatory processes and diseases in dogs associated with the activity of inducible cyclo-oxygenase-2 (COX-2), while at the same time reducing or eliminating undesirable side effects associated with simultaneous inhibition of the activity of constitutive cyclo-oxygenase-1 (COX-1) by selectively inhibiting COX-2 activity with reference to COX-1 activity, wherein the selectivity ratio or COX-2:COX-1 activity inhibition is at least 3:1 based on ex vivo inhibition levels measured in whole blood; the inhibitor is a member selected from the group of anti-inflammatory compounds consisting essentially of salicylic acid derivatives, p-aminophenol derivatives, indole and indene acetic acids, heteroaryl acetic acids, arylpropionic acids, anthranilic acids, enolic acids, and alkanones; the inhibitor in particular is comprised of (+)(S)-enantiomer of 6-chloro-α-methyl-9H-carbazole-2-acetic acid.
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- Effect of micelles and mixed micelles on efficiency and selectivity of antibiotic-based capillary electrophoretic enantioseparations.
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Vancomycin (an oligophenolic, glycopeptide, macrocyclic antibiotic) has been shown to be a superb chiral selector for anionic and neutral compounds. It was found that adding sodium dodecyl sulfate to the run buffer increased efficiency by over 1 order of magnitude, decreased analysis times, and reversed the elution order of the enantiomers. This allows for control of the retention order as well as the resolution of enantiomers in complex mixtures in a single run. A mechanism is proposed which explains all of the observed effects and is verified experimentally. Since vancomycin is present in both the micelle and in free solution, previously proposed micelle-selector models are, at best, limiting cases. A general equation is derived which can be used to describe all possible interactions, including those with the capillary wall, if needed. Also, it is shown that electrophoretic mobilities and not migration times must be used to calculate binding constants of a solute to the micelle, the chiral selector, or both. Furthermore, it is shown that a neutral marker molecule cannot be used to accurately correct mobilities that have been altered due to changes in solution viscosity. While this work utilizes the practical vancomycin-micelle system, the general conclusions and theory apply to most other analogous CE systems as well.
- Rundlett,Armstrong
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p. 2088 - 2095
(2007/10/02)
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