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Wenchao Xing - One of the best experts on this subject based on the ideXlab platform.
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preparation and characterization of mono pegylated consensus interferon by a novel polyethylene glycol derivative
Journal of Chemical Technology & Biotechnology, 2006Co-Authors: Qiang Yun, Wenchao XingAbstract:Traditional PEGylation strategy of peptide and protein usually results in heterogeneous products wide molecular weight distribution. Mono-PEGylated consensus interferon (C-IFN) with homogeneous molecular weight was prepared by a novel methoxypolyethylene glycol (mPEG) derivative. 2-Fluoro-1-methylpyridinium Toluene-4-Sulfonate (FMP) was applied to activate mPEG and a novel functionalized mPEG derivative (FMP-mPEG) was obtained. The reactivity of FMP-mPEG toward amino groups of C-IFN was evaluated, and the heterogeneity of PEGylated protein was identified by high-performance size-exclusion chromatography (HPSEC) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). Finally, the PEGylated C-IFN was separated from intact protein by cation-exchange chromatography. The results indicated that PEGylation process was dependent on pH dramatically and the modification degree was increased with the increasing molar excess of FMP-mPEG. Under optimized condition, mono-PEGylated C-IFN with molecule weight of 24.64 kDa was achieved. Further investigation of in vitro biological activities demonstrated that about 88% of antiviral activity was maintained by the mono-PEGylated C-IFN.
Qiang Yun - One of the best experts on this subject based on the ideXlab platform.
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preparation and characterization of mono pegylated consensus interferon by a novel polyethylene glycol derivative
Journal of Chemical Technology & Biotechnology, 2006Co-Authors: Qiang Yun, Wenchao XingAbstract:Traditional PEGylation strategy of peptide and protein usually results in heterogeneous products wide molecular weight distribution. Mono-PEGylated consensus interferon (C-IFN) with homogeneous molecular weight was prepared by a novel methoxypolyethylene glycol (mPEG) derivative. 2-Fluoro-1-methylpyridinium Toluene-4-Sulfonate (FMP) was applied to activate mPEG and a novel functionalized mPEG derivative (FMP-mPEG) was obtained. The reactivity of FMP-mPEG toward amino groups of C-IFN was evaluated, and the heterogeneity of PEGylated protein was identified by high-performance size-exclusion chromatography (HPSEC) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). Finally, the PEGylated C-IFN was separated from intact protein by cation-exchange chromatography. The results indicated that PEGylation process was dependent on pH dramatically and the modification degree was increased with the increasing molar excess of FMP-mPEG. Under optimized condition, mono-PEGylated C-IFN with molecule weight of 24.64 kDa was achieved. Further investigation of in vitro biological activities demonstrated that about 88% of antiviral activity was maintained by the mono-PEGylated C-IFN.
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Novel polyethylene glycol derivative suitable for the preparation of mono-PEGylated protein.
Biotechnology letters, 2005Co-Authors: Qiang Yun, Ting Chen, Guifeng ZhangAbstract:A novel methoxypolyethylene glycol (mPEG) derivative, containing a reactive group of 1-methyl pyridinium Toluene-4-Sulfonate, was synthesized and characterized. The mPEG derivative was successfully conjugated with two proteins: recombinant human granulocyte-colony stimulating factor (rhG-CSF) and consensus interferon (C-IFN). Homogeneous mono-PEGylated proteins were obtained which were identified by high performance size-exclusion chromatography and MALDI-TOF mass spectrometry. The biological activities of the mono-PEGylated rhG-CSF and the mono-PEGylated C-IFN were maintained at 90% and 88%, respectively.
Semak Vladislav - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of 1S-ethyl-4-substituted quinolizidines and other potentially bioactive compounds
'Edicions de la Universitat de Barcelona', 2012Co-Authors: Semak VladislavAbstract:Esta Tesis Doctoral se presenta como Compendio de publicaciones. Los capítulos en los que se ha dividido la presente Tesis son los siguientes: Capítulo 1 – parte A: Enantioselective, Protecting Group-Free Synthesis of 1S-Ethyl-4-Substituted Quinolizidines Se ha descrito una síntesis enantioselectiva que no implica grupos protectores para acceder a la quinolizidina clave 6 a partir de la lactama bicíclica derivada de fenilglicinol 1. La adición de un reactivo organometálico a 6 ocurre de manera estereoselectiva para conducir a las quinolizidinas 1S-etil-4-sustituidas 4-epi-207I y 7-9. Siguiendo una secuencia sintética análoga, se preparó el compuesto 9a-epi-6. Sin embargo, la adición de reactivos de Grignard al compuesto 9a-epi-6 no ocurre de manera estereoselectiva. Capítulo 1 – parte B: A practical procedure for the removal of the phenylethanol moiety from phenylglycinol-derived lactams Las lactamas bicíclicas no racémicas derivadas de fenilglicinol se han relevado como intermedios clave en la preparación de compuestos nitrogenados enantiopuros. En este capítulo se describe la eliminación del inductor quiral de piperidonas sustituidas utilizando aire u oxígeno en medio básico. Capítulo 2: Synthesis of triheptanoin and formulation as a solid diet for rodents En el presente estudio se describe la síntesis eficaz de triheptanoina de elevada pureza a partir de glicerol y ácido heptanoico, en presencia de carbono sulfonado como catalizador. La triheptanoina se formula como un sólido estable para que constituya la base de una dieta cetogénica mediante la combinación de custro gentes de formulación comerciales; dos tipos de sílica, celulosa microcristalina y talco. La adecuación de la dieta se prueba en ratones C57BI/6 en un periodo de 15 días, comparando el estado general y el cambio de peso corporal. Capítulo 3: Toluene dioxygenase (TDO) mediated oxidation of halogen-substituted benzoate esters Una serie de esteres benzoicos metílicos sustituidos en o-, m- y p- se han sometido a hidroxilación enzimática via fermetación con E. coli JM109 8pDTG601A). Solo se metabolizaron los benzoatos sustituidos en orto. El 2-fluorobenzoato de metilo produjo regioselectivamente solo un diol mientras que el 2-cloro, 2-bromo y 2-iodobenzoato de metilo proporciona una mezcla de regioisómeros. Capítulo 4: Dauben–Michno oxidative transposition of allylic cyanohydrins Enantiomeric switch of (–)-carvone to (+)-carvone Cuando cianohidrinas alílicas se someten a la reacción de oxidación de Dauben-Michno a bajas temperaturas se accede a β-cianoenonas en buenos a excelentes rendimientos. El potencial de esta trasposición oxidativa se pone de manifiesto en enonas que contienen un plano latente de simetría como por ejemplo la conversión de la (-)-carvona en su enantiomero.A dissertation submitted by Vladislav SEMAK to obtain a doctoral degree from University of Barcelona. This thesis was developed under the supervision of Dr. Carmen Escolano Mirón from Faculty of Pharmacy, University of Barcelona. This doctoral thesis is presented as a compendium of publications. The thesis is divided in four chapters: CHAPTER 1 – PART A: Enantioselective, Protecting Group-Free Synthesis of 1S-Ethyl-4-Substituted Quinolizidines (Amat, M.; Semak, V.; Escolano, C.; Molins, E.; Bosch, J. Org. Biomol. Chem. 2012, 10, 6866-6875.) A practical enantioselective protecting group-free four-step route to the key quinolizidinone 6 from phenylglycinol-derived bicyclic lactam 1 is reported. The organometallic addition reaction upon 6 takes place stereoselectively to give 1-ethyl-4-substituted quinolizidines 4-epi-207I and 7-9. Following a similar synthetic sequence, 9a-epi-6 is also accessed. However, the addition of Grignard reagents upon 9a-epi-6 proceeds in a non-stereoselective manner. In order to gain insight into the different stereochemical outcome in the two series, theoretical calculations on the iminium salts A and B have been performed. The study concludes that the addition of the hydride, which is the step that determines the configuration of the final products, occurs in a stereoelectronic controlled manner. CHAPTER 1 – PART B: A practical procedure for the removal of the phenylethanol moiety from phenylglycinol-derived lactams (V. Semak; C, Escolano; C. Arróniz; J. Bosch; M. Amat Tetrahedron: Asymmetry 2010, 21, 2542-2549.) Chiral non-racemic bicyclic lactams derived from phenylglycinol have been appointed as key building blocks for the preparation of enantiopure nitrogen compounds. The removal of the chiral inductor leading to substituted piperidones by using air or oxygen in basic media is presented in this chapter. CHAPTER 2: Synthesis of triheptanoin and formulation as a solid diet for rodents (Semak, V.; Semakova, J.; Halbaut, L.; Asó, E.; Ferrer, I.; Calpena, A.; Escolano, C.; Perales, J. C. Eur. J. Lipid Sci. Technol. 2012, 114, 889-895.) In the present study, we successfully synthesized triheptanoin to the highest standards of purity from glycerol and heptanoic acid, using sulfonated charcoal as a catalyst. Triheptanoin oil was then formulated as a solid, stable and palatable preparation using a ketogenic base and a combination of four commercially available formulation agents: hydrophilic fumed silica, hydrophobic fumed silica, microcrystalline cellulose, and talc. Diet compliance and safety was tested on C57Bl/6 mice over a 15-week period, comparing overall status and body weight change. CHAPTER 3: Toluene dioxygenase mediated oxidation of halogen-substituted benzoate esters (Semak, V.; Metcalf, T. A.; Endoma-Arias, M. A. A.; Mach, P.; Hudlicky, T. Org. Biomol. Chem. 2012, 10, 4407-4416.) A series of ortho-, meta-, and para-halogen-substituted methyl benzoate esters was subjected to enzymatic dihydroxylation via the whole-cell fermentation with E. coli JM109 (pDTG601A). Only ortho-substituted benzoates were metabolized. Methyl 2-fluorobenzoate yielded one diol regioselectively whereas methyl 2-chloro-, methyl 2-bromo- and methyl 2-iodobenzoates each yielded a mixture of regioisomers. Absolute stereochemistry was determined for all new metabolites. Computational analysis of these results and a possible rationale for the regioselectivity of the enzymatic dihydroxylation is advanced. CHAPTER 4: Dauben–Michno oxidative transposition of allylic cyanohydrins. Enantiomeric switch of (–)-carvone to (+)-carvone. (Hudlicky, J. R.; Werner, L.; Semak, V.; Simionescu, R.; Hudlicky, T. Can. J. Chem. 2011, 89, 535-543.) Allylic cyanohydrins were subjected to Dauben–Michno oxidation at low temperatures to provide β-cyanoenones in good to excellent yields. The potential of this oxidative transposition as a means of an enantiomeric switch of enones containing a latent plane of symmetry was tested by conversion of (–)-carvone to its enantiomer
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Synthesis of 1S-ethyl-4-substituted quinolizidines and other potentially bioactive compounds
'Edicions de la Universitat de Barcelona', 2012Co-Authors: Semak VladislavAbstract:[spa] Esta Tesis Doctoral se presenta como Compendio de publicaciones. Los capítulos en los que se ha dividido la presente Tesis son los siguientes: Capítulo 1 – parte A: Enantioselective, Protecting Group-Free Synthesis of 1S-Ethyl-4-Substituted Quinolizidines Se ha descrito una síntesis enantioselectiva que no implica grupos protectores para acceder a la quinolizidina clave 6 a partir de la lactama bicíclica derivada de fenilglicinol 1. La adición de un reactivo organometálico a 6 ocurre de manera estereoselectiva para conducir a las quinolizidinas 1S-etil-4-sustituidas 4-epi-207I y 7-9. Siguiendo una secuencia sintética análoga, se preparó el compuesto 9a-epi-6. Sin embargo, la adición de reactivos de Grignard al compuesto 9a-epi-6 no ocurre de manera estereoselectiva. Capítulo 1 – parte B: A practical procedure for the removal of the phenylethanol moiety from phenylglycinol-derived lactams Las lactamas bicíclicas no racémicas derivadas de fenilglicinol se han relevado como intermedios clave en la preparación de compuestos nitrogenados enantiopuros. En este capítulo se describe la eliminación del inductor quiral de piperidonas sustituidas utilizando aire u oxígeno en medio básico. Capítulo 2: Synthesis of triheptanoin and formulation as a solid diet for rodents En el presente estudio se describe la síntesis eficaz de triheptanoina de elevada pureza a partir de glicerol y ácido heptanoico, en presencia de carbono sulfonado como catalizador. La triheptanoina se formula como un sólido estable para que constituya la base de una dieta cetogénica mediante la combinación de custro gentes de formulación comerciales; dos tipos de sílica, celulosa microcristalina y talco. La adecuación de la dieta se prueba en ratones C57BI/6 en un periodo de 15 días, comparando el estado general y el cambio de peso corporal. Capítulo 3: Toluene dioxygenase (TDO) mediated oxidation of halogen-substituted benzoate esters Una serie de esteres benzoicos metílicos sustituidos en o-, m- y p- se han sometido a hidroxilación enzimática via fermetación con E. coli JM109 8pDTG601A). Solo se metabolizaron los benzoatos sustituidos en orto. El 2-fluorobenzoato de metilo produjo regioselectivamente solo un diol mientras que el 2-cloro, 2-bromo y 2-iodobenzoato de metilo proporciona una mezcla de regioisómeros. Capítulo 4: Dauben–Michno oxidative transposition of allylic cyanohydrins Enantiomeric switch of (–)-carvone to (+)-carvone Cuando cianohidrinas alílicas se someten a la reacción de oxidación de Dauben-Michno a bajas temperaturas se accede a β-cianoenonas en buenos a excelentes rendimientos. El potencial de esta trasposición oxidativa se pone de manifiesto en enonas que contienen un plano latente de simetría como por ejemplo la conversión de la (-)-carvona en su enantiomero.[eng] A dissertation submitted by Vladislav SEMAK to obtain a doctoral degree from University of Barcelona. This thesis was developed under the supervision of Dr. Carmen Escolano Mirón from Faculty of Pharmacy, University of Barcelona. This doctoral thesis is presented as a compendium of publications. The thesis is divided in four chapters: CHAPTER 1 – PART A: Enantioselective, Protecting Group-Free Synthesis of 1S-Ethyl-4-Substituted Quinolizidines (Amat, M.; Semak, V.; Escolano, C.; Molins, E.; Bosch, J. Org. Biomol. Chem. 2012, 10, 6866-6875.) A practical enantioselective protecting group-free four-step route to the key quinolizidinone 6 from phenylglycinol-derived bicyclic lactam 1 is reported. The organometallic addition reaction upon 6 takes place stereoselectively to give 1-ethyl-4-substituted quinolizidines 4-epi-207I and 7-9. Following a similar synthetic sequence, 9a-epi-6 is also accessed. However, the addition of Grignard reagents upon 9a-epi-6 proceeds in a non-stereoselective manner. In order to gain insight into the different stereochemical outcome in the two series, theoretical calculations on the iminium salts A and B have been performed. The study concludes that the addition of the hydride, which is the step that determines the configuration of the final products, occurs in a stereoelectronic controlled manner. CHAPTER 1 – PART B: A practical procedure for the removal of the phenylethanol moiety from phenylglycinol-derived lactams (V. Semak; C, Escolano; C. Arróniz; J. Bosch; M. Amat Tetrahedron: Asymmetry 2010, 21, 2542-2549.) Chiral non-racemic bicyclic lactams derived from phenylglycinol have been appointed as key building blocks for the preparation of enantiopure nitrogen compounds. The removal of the chiral inductor leading to substituted piperidones by using air or oxygen in basic media is presented in this chapter. CHAPTER 2: Synthesis of triheptanoin and formulation as a solid diet for rodents (Semak, V.; Semakova, J.; Halbaut, L.; Asó, E.; Ferrer, I.; Calpena, A.; Escolano, C.; Perales, J. C. Eur. J. Lipid Sci. Technol. 2012, 114, 889-895.) In the present study, we successfully synthesized triheptanoin to the highest standards of purity from glycerol and heptanoic acid, using sulfonated charcoal as a catalyst. Triheptanoin oil was then formulated as a solid, stable and palatable preparation using a ketogenic base and a combination of four commercially available formulation agents: hydrophilic fumed silica, hydrophobic fumed silica, microcrystalline cellulose, and talc. Diet compliance and safety was tested on C57Bl/6 mice over a 15-week period, comparing overall status and body weight change. CHAPTER 3: Toluene dioxygenase mediated oxidation of halogen-substituted benzoate esters (Semak, V.; Metcalf, T. A.; Endoma-Arias, M. A. A.; Mach, P.; Hudlicky, T. Org. Biomol. Chem. 2012, 10, 4407-4416.) A series of ortho-, meta-, and para-halogen-substituted methyl benzoate esters was subjected to enzymatic dihydroxylation via the whole-cell fermentation with E. coli JM109 (pDTG601A). Only ortho-substituted benzoates were metabolized. Methyl 2-fluorobenzoate yielded one diol regioselectively whereas methyl 2-chloro-, methyl 2-bromo- and methyl 2-iodobenzoates each yielded a mixture of regioisomers. Absolute stereochemistry was determined for all new metabolites. Computational analysis of these results and a possible rationale for the regioselectivity of the enzymatic dihydroxylation is advanced. CHAPTER 4: Dauben–Michno oxidative transposition of allylic cyanohydrins. Enantiomeric switch of (–)-carvone to (+)-carvone. (Hudlicky, J. R.; Werner, L.; Semak, V.; Simionescu, R.; Hudlicky, T. Can. J. Chem. 2011, 89, 535-543.) Allylic cyanohydrins were subjected to Dauben–Michno oxidation at low temperatures to provide β-cyanoenones in good to excellent yields. The potential of this oxidative transposition as a means of an enantiomeric switch of enones containing a latent plane of symmetry was tested by conversion of (–)-carvone to its enantiomer
Hussaini Mohammed Majiya - One of the best experts on this subject based on the ideXlab platform.
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Photosensitiser functionalised nanofiber fabric for efficient light driven water disinfection
2017Co-Authors: Hussaini Mohammed MajiyaAbstract:Sunlight-driven water disinfection system could help provide clean water to some of the world’s poorest regions where contaminated surface water is a major public health problem and bright solar irradiation is available for free. In this work, photosensitiser - 5, 10, 15, 20-tetrakis (1-methyl-4-pyridinio) porphyrin tetra p-toluene sulfonate (TMPyP) was chosen and immobilised onto chitosan nanofiber mats and chitosan membranes for photodynamic disinfection of water since preliminary studies with TMPyP in solution showed it caused a high rate of photodynamic inactivation (PDI) of model viral organisms (bacteriophages MS2 and Qβ, murine norovirus and bovine enterovirus 2). Native gel electrophoresis, SDS-PAGE and western blotting, TEM and DLS were used to analyse pre- and post-PDI samples of the model viruses. The rate of PDI in model viruses was in the order MS2 > phage Qβ > murine norovirus > bovine enterovirus 2. Our data showed that PDI caused aggregation of MS2 particles and crosslinking of MS2 coat protein. However, the aggregation and crosslinking did not correlate to the rate of PDI we observed in MS2. Using sequence specific antibodies raised against MS2 A-protein (host attachment protein), our results suggest that the rate of PDI is relative to loss of antigenicity of sites on the A-protein. The differences in the rate of PDI were compared to amino acid compositions and surface accessibility of host attachment proteins/sites of the model viruses. Possible modes of action are discussed as a means to gaining insight to the targets and mechanisms of PDI of viruses. Chitosan electrospun nanofibers and chitosan membranes were modified by pyromellitic dianhydride in order to introduce carboxyl groups and facilitate adsorption of the cationic TMPyP. The physico-chemical properties of these modified nanofibers and membranes were investigated by microscopy, absorption spectroscopy, Fourier-transform infrared spectroscopy and Midland surface blotting approaches.The chitosan nanofiber/membrane-TMPyP composite showed photodynamic inactivation of MS2 and E. coli BL21.
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TMPyP functionalised chitosan membrane for efficient sunlight driven water disinfection
Journal of water process engineering, 2017Co-Authors: Hussaini Mohammed Majiya, Kaniz F. Chowdhury, Nicola J Stonehouse, Paul A. MillnerAbstract:Abstract Sunlight-driven water disinfection system could help provide clean water to some of the world’s poorest people. In this study, chitosan membranes were modified by pyromellitic dianhydride in order to introduce carboxyl groups and facilitate adsorption of the highly basic photosensitiser − 5, 10, 15, 20-tetrakis (1-methyl-4-pyridinio) porphyrin tetra p-toluene sulfonate (TMPyP). The physico-chemical properties of these modified membranes were investigated by microscopy, absorption spectroscopy and Midland surface blotting approaches. The chitosan membrane-TMPyP composite showed photodynamic inactivation of bacteriophage MS2 and E. coli BL21. For photodynamic inactivation under stationary conditions, complete inactivation of MS2 was observed after 90 min illumination at a light intensity of 32 mW cm−2 (which equates to around 3% of bright mid-day time sunlight under clear sky conditions in sub-Saharan Africa). For a flowing system, complete inactivation of MS2 was observed for sample flowing at 0.33 ml/min and passed over the surface of the modified membranes while being illuminated. Reduction of approximately 3 log PFU/ml were observed for samples passed just once over the membranes under the same conditions. With E. coli, under the same stationary conditions, a reduction of 3 log CFU/ml was observed. Each TMPyP functionalised chitosan membrane was used at least three times for the photodynamic inactivation of both MS2 and E. coli BL21 without any detectable loss of inactivation capacity. The re-usability of the membranes will reduce cost and increase the advantage of using an environmental-friendly technology for water disinfection.
P Ramasamy - One of the best experts on this subject based on the ideXlab platform.
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growth and characterization of 2 amino 4 picolinium toluene sulfonate single crystal
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2011Co-Authors: Anandha G Babu, P RamasamyAbstract:Abstract 2-Amino-4-picolinium toluene sulfonate (2A4PTS), a new organic material, was synthesized and grown as single crystals in room temperature by slow evaporation solution growth technique using water as solvent. The crystal structure of 2A4PTS has been determined using single crystal X-ray diffraction studies. 2A4PTS belongs to monoclinic crystal system. The molecular arrangements in the crystal were studied. The structural perfection of the grown crystals has been analysed by high-resolution X-ray diffraction (HRXRD) rocking curve measurements. Fourier transform infrared (FTIR) spectral studies have been performed to identify the functional groups. The optical transmittance window and the lower cutoff wavelength of the 2A4PTS have been identified by UV–Vis–NIR studies. The nonlinear optical properties have been investigated by Z-scan method. The nonlinear refractive index and linear absorption coefficient of the 2A4PTS are found to be in the order of 10−8 cm2/W and 10−4 cm/W, respectively. The laser induced surface damage threshold for the grown crystal was measured using Nd:YAG laser. Thermal analysis carried out on the compound reveals that 2A4PTS is stable up to 133 °C. The microhardness test was carried out and the load dependent hardness was measured.