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1.
Protein Expr Purif ; 192: 106030, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34920133

RESUMO

Nanobodies (Nbs) are single-domain antibodies, which have potential application value in tumor-targeted therapy, immunotherapy, diagnostic probe, and molecular imaging. Typically, Nbs are captured by affinity chromatography via the addition of specific fusion tags at their N or C terminus. Nerve growth factor (NGF), which regulates the growth and development of peripheral and central neurons, maintains neuronal survival and plays a key role in both arthritis and acute and chronic pain. In this study, a method for capture and purification of an untagged Nb (anti-NGF Nb) by mixed weak cation chromatography and cation exchange chromatography was established. First, pH 4.0-5.0 was demonstrated to be the optimal loading condition for Capto MMC to capture anti-NGF by the design of experiments (DOE). Furthermore, high purity and yield products can be obtained at laboratory scale and commercial production scale by adjusting the protein pH. Additionally, direct capture of anti-NGF Nb using Capto MMC without adjusting anti-NGF Nb harvest pH was investigated. The anti-NGF Nb captured by Capto MMC was 67.2% yield, 94.5% monomer purity, and host cell protein (HCP) was reduced from 74,931 ppm to 484 ppm. The anti-NGF Nb that were further purified using Capto S ImpAct achieved 84.5% yield and 99.2% purity and 77 ppm of HCP. The scaling-up process was consistent with the results of the optimized process, further demonstrating the feasibility of this method. This outcome provides a highly promising and competitive alternative to affinity chromatography-based processing strategies for Nbs.


Assuntos
Cromatografia por Troca Iônica/métodos , Anticorpos de Cadeia Única/isolamento & purificação , Adsorção , Resinas de Troca de Cátion/química , Anticorpos de Cadeia Única/química , Anticorpos de Cadeia Única/genética , Anticorpos de Cadeia Única/metabolismo
2.
J Chromatogr A ; 1634: 461681, 2020 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-33212368

RESUMO

5'-ribonucleotides including adenosine 5'-monophosphate (AMP), cytidine 5'-monophsphate (CMP), guanosine 5'-monophosphate (GMP) and uridine 5'-monophosphate (UMP) have been widely used in the food and pharmaceutical industries. This work focused on the assessment of mass transfer process and separation mechanism of four 5'-ribonucleotides and counter-ion Na+ on the strong cation exchange resin NH-1. The intraparticle diffusion was determined as the rate-limiting step for the mass transfer of AMP, CMP, GMP, and Na+ on the resin NH-1 through the Boyd model. Meanwhile, a homogeneous surface diffusion model (HSDM) combing ion exchange and physical adsorption was proposed and tested against adsorption kinetic data in the batch adsorption systems. The fixed-bed film-surface diffusion model based on the HSDM was then developed and successfully predicted the concentration profiles of 5'-ribonucleotides and the change of pH at the outlet of the fixed-bed in the dynamic adsorption and separation process. Finally, the separation mechanism of 5'-ribonucleotides was presented combining model prediction and experimental results. The separation of UMP, GMP and CMP were mainly based on their differences in isoelectric points, while that of AMP and CMP were lied with the discrepancy of their physical adsorption binding capacity with the resin NH-1.


Assuntos
Resinas de Troca de Cátion/química , Cromatografia/métodos , Ribonucleotídeos/isolamento & purificação , Ácidos/química , Monofosfato de Adenosina/isolamento & purificação , Adsorção , Difusão , Guanosina Monofosfato/isolamento & purificação , Focalização Isoelétrica , Cinética , Ribonucleotídeos/química , Uridina Monofosfato/isolamento & purificação
3.
Molecules ; 25(20)2020 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-33066650

RESUMO

44Sc has favorable properties for cancer diagnosis using Positron Emission Tomography (PET) making it a promising candidate for application in nuclear medicine. The implementation of its production with existing compact medical cyclotrons would mean the next essential milestone in the development of this radionuclide. While the production and application of 44Sc has been comprehensively investigated, the development of specific targetry and irradiation methods is of paramount importance. As a result, the target was optimized for the 44Ca(p,n)44Sc nuclear reaction using CaO instead of CaCO3, ensuring decrease in target radioactive degassing during irradiation and increased radionuclidic yield. Irradiations were performed at the research cyclotron at the Paul Scherrer Institute (~11 MeV, 50 µA, 90 min) and the medical cyclotron at the University of Bern (~13 MeV, 10 µA, 240 min), with yields varying from 200 MBq to 16 GBq. The development of targetry, chemical separation as well as the practical issues and implications of irradiations, are analyzed and discussed. As a proof-of-concept study, the 44Sc produced at the medical cyclotron was used for a preclinical study using a previously developed albumin-binding prostate-specific membrane antigen (PSMA) ligand. This work demonstrates the feasibility to produce 44Sc with high yields and radionuclidic purity using a medical cyclotron, equipped with a commercial solid target station.


Assuntos
Ciclotrons , Tomografia por Emissão de Pósitrons/métodos , Radioisótopos , Escândio , Albuminas/metabolismo , Animais , Antígenos de Superfície , Compostos de Cálcio/química , Resinas de Troca de Cátion/química , Desenho de Equipamento , Feminino , Glutamato Carboxipeptidase II , Hélio/química , Humanos , Marcação por Isótopo/métodos , Camundongos Nus , Neoplasias Experimentais/diagnóstico por imagem , Óxidos/química , Estudo de Prova de Conceito , Radioisótopos/química , Compostos Radiofarmacêuticos/química , Escândio/química , Ensaios Antitumorais Modelo de Xenoenxerto
4.
Int J Mol Sci ; 21(21)2020 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-33114195

RESUMO

This study examines the mechanisms of adsorption of anthocyanins from model aqueous solutions at pH values of 3, 6, and 9 by ion-exchange resins making the main component of heterogeneous ion-exchange membranes. This is the first report demonstrating that the pH of the internal solution of a KU-2-8 aromatic cation-exchange resin is 2-3 units lower than the pH of the external bathing anthocyanin-containing solution, and the pH of the internal solution of some anion-exchange resins with an aromatic (AV-17-8, AV-17-2P) or aliphatic (EDE-10P) matrix is 2-4 units higher than the pH of the external solution. This pH shift is caused by the Donnan exclusion of hydroxyl ions (in the KU-2-8 resin) or protons (in the AV-17-8, AV-17-2P, and EDE-10P resins). The most significant pH shift is observed for the EDE-10P resin, which has the highest ion-exchange capacity causing the highest Donnan exclusion. Due to the pH shift, the electric charge of anthocyanin inside an ion-exchange resin differs from its charge in the external solution. At pH 6, the external solution contains uncharged anthocyanin molecules. However, in the AV-17-8 and AV-17-2P resins, the anthocyanins are present as singly charged anions, while in the EDE-10P resin, they are in the form of doubly charged anions. Due to the electrostatic interactions of these anions with the positively charged fixed groups of anion-exchange resins, the adsorption capacities of AV-17-8, AV-17-2P, and EDE-10P were higher than expected. It was established that the electrostatic interactions of anthocyanins with the charged fixed groups increase the adsorption capacity of the aromatic resin by a factor of 1.8-2.5 compared to the adsorption caused by the π-π (stacking) interactions. These results provide new insights into the fouling mechanism of ion-exchange materials by polyphenols; they can help develop strategies for membrane cleaning and for extracting anthocyanins from juices and wine using ion-exchange resins and membranes.


Assuntos
Antocianinas/química , Resinas de Troca Iônica/química , Adsorção , Resinas de Troca Aniônica/química , Resinas de Troca de Cátion/química , Concentração de Íons de Hidrogênio , Estrutura Molecular , Eletricidade Estática
5.
J Sep Sci ; 43(22): 4123-4130, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32914492

RESUMO

We describe the synthesis of polymer monoliths inside polypropylene tubes from ink pens. These tubes are cheap, chemically stable, and resistant to pressure. UV-initiated grafting with 5 wt% benzophenone in methanol for 20 min activated the internal surface, thus enabling the covalent binding of ethylene glycol dimethacrylate, also via photografting. The pendant vinyl groups attached a poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) monolith prepared via photopolymerization. These tubes measured 100-110 mm long, with 2 mm of internal diameter. The parent monoliths were functionalized with Na2 SO3 or iminodiacetate to produce strong and weak cation exchangers, respectively. The columns exhibited permeabilities varying from 2.7 to 3.3 × 10-13  m2 , which enabled the separation of proteins at 500 µL/min and back pressures <2.8 MPa. Neither structure collapse nor monolith detachment occurred at flow rates as high as 2.0 mL/min, which produced back pressures between 6.9 and 9.0 MPa. The retention times of ovalbumin, ribonuclease A, cytochrome C, and lysozyme in salt gradient at pH 7.0 followed the order of increasing isoelectric points, confirming the cation exchange mechanism. Separation and determination of lysozyme in egg white proved the applicability of the columns to the analysis of complex samples.


Assuntos
Citocromos c/isolamento & purificação , Tinta , Muramidase/isolamento & purificação , Ovalbumina/isolamento & purificação , Polipropilenos/química , Ribonuclease Pancreático/isolamento & purificação , Resinas de Troca de Cátion/química , Cromatografia por Troca Iônica , Citocromos c/química , Muramidase/química , Muramidase/metabolismo , Ovalbumina/química , Ribonuclease Pancreático/química
6.
Artigo em Inglês | MEDLINE | ID: mdl-31812005

RESUMO

Pingyangmycin (PYM) and boanmycin (BAM), two individual components of bleomycin (bleomycin A5 and bleomycin A6), are glycopeptide antitumor antibiotics. An efficient procedure for the preparation of PYM and BAM from Streptomyces verticillus var. pingyangensis fermentation broth using macroporous cation-exchange (MCE) resin followed by medium-pressure preparative liquid chromatography (MPLC) based on monodisperse poly(styrene-co-divinylbenzene) (p(st-dvb)) microspheres was investigated in this paper. Nine frequently used MCE resins were screened by static adsorption and desorption to enrich PYM and BAM fromthe fermentation broth, and D157 resin was found to be the most effective. After one run of column-based dynamic adsorption and desorption, the contents of PYM and BAM were increased by factors of 13.8 and 12.1 with recovery yields of 84.21% and 81.47%, respectively. The enriched samples were subjected to MPLC with columns prepacked with the PolyRP 10-300 microspheres. The operational parameters of the MPLC, including the stationary phase and mobile phase compositions, sample/stationary phase ratio, sample loading scale and flow rate, were screened and optimized. The results showed that the separation and purification for PYM and BAM by MPLC were dramatically improved with a mobile phase modifier of 0.15 mol/L ammonium chloride aqueoussolution, a flow rate of 10 mL/min and a sample/stationary phase ratio of 1.0:100 (m/v, g/mL), and PYM and BAM with purities of more than 98.65% and 99.12% were obtained, respectively. The total recoveries of PYM and BAM reached 75.38% and 70.31%. The separation and purification method is simple, efficient, energy-saving, environmentally friendly and suitable for the large-scale preparation of high-purity PYM and BAM from Streptomyces verticillus var. pingyangensis fermentation broth.


Assuntos
Bleomicina/análogos & derivados , Resinas de Troca de Cátion/química , Cromatografia de Fase Reversa/métodos , Streptomyces/química , Bleomicina/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Fermentação , Reprodutibilidade dos Testes , Streptomyces/metabolismo
7.
Chemosphere ; 211: 1091-1097, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30223324

RESUMO

Cation exchange resins have proved to be efficient in removing precursors of N-nitrosodimethylamine (NDMA). NDMA is a probable human carcinogen with a calculated lifetime cancer risk of 10-6 at 0.7 ng/L in drinking water. This paper investigated the effect of pH and calcium levels on the removal of NDMA precursors using a cation exchange resin. At pH 5 and 7, 30-50% of NDMA precursors, measured by formation potentials (FPs) changes before and after the treatment, were removed by Plus resin. However, increases in NDMA FPs were observed after the treatment at pH 10 indicating that NDMA precursors were released from the resin. NDMA FPs removals in samples containing 15 and 115 mg/L Ca2+ were 40% and -10% after the ion exchange treatments at pH 7, respectively. It was found that in the presence of high concentration of calcium only one out of four cation exchange resins released NDMA precursors (probably due to manufacturing impurities). Also, the release of NDMA precursors depended on the calcium concentration and the contact time of the resin with the solution containing calcium. Nonetheless, NDMA precursors release from the resin subsided significantly with increasing the number of regeneration cycles of the resin.


Assuntos
Resinas de Troca de Cátion/química , Dimetilnitrosamina/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Cálcio/farmacologia , Dimetilnitrosamina/análise , Água Potável/química , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/análise , Purificação da Água/métodos
8.
J Chromatogr A ; 1574: 60-70, 2018 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-30220427

RESUMO

We are currently examining the potential of amphipathic cationic α-helical peptides as a new generation of peptide standards for both cation-exchange high-performance liquid chromatography and reversed-phase chromatography. Thus, amphipathic peptides are particularly suitable for high-performance liquid chromatography standards due to the preferred binding of the non-polar face to the hydrophobic stationary phase of reversed-phase packings or the preferred binding of the polar face to the charged/hydrophilic stationary phase of cation-exchange packings. The ability of different reversed-phase or cation-exchange matrices to separate mixtures of peptide standards with only subtle hydrophilicity/hydrophobicity variations in both the non-polar and polar face of the peptides can then be assessed. Currently, we have designed de novo a mixture of six 26-residue all D-conformation amphipathic cationic α-helical peptides with a single, positively charged lysine residue in the center of the non-polar face and an increasing number of lysine residues (4-9 residues) replacing neutral residues in the polar face, resulting in an overall net positive charge of +5 to +10. Thus, the non-polar, preferred reversed-phase chromatography binding face remains constant, with only the polar face varying in hydrophilicity/hydrophobicity. Interestingly, even with the non-polar face remaining constant, reversed-phase columns of varying functional group properties (e.g., C8, C18, phenyl, polar endcapped, polar embedded) and porosity (porous versus superficially porous) were able to separate the six peptides in aq. TFA/acetonitrile gradients, albeit with different selectivities. The value of the standards in cation-exchange chromatography was expressed by monitoring the requirement of acetonitrile (0-40% in the mobile phase) to overcome hydrophobic interactions of the peptides with the cation-exchange matrix matrix when eluting with sodium perchlorate gradients at pH 6.5. Interestingly, the resolution of the higher charged peptides (+8,+9,+10) was particularly sensitive to acetonitrile levels. Our results clearly demonstrate the excellent potential of these novel peptide standards to enable optimal column choice and mobile phase conditions for reversed-phase chromatography and cation-exchange chromatography for peptide separations.


Assuntos
Técnicas de Química Analítica/métodos , Cromatografia Líquida de Alta Pressão , Cromatografia de Fase Reversa , Peptídeos/isolamento & purificação , Padrões de Referência , Acetonitrilas/química , Resinas de Troca de Cátion/química , Técnicas de Química Analítica/instrumentação , Interações Hidrofóbicas e Hidrofílicas , Peptídeos/química
9.
Water Sci Technol ; 2017(3): 770-781, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30016295

RESUMO

A magnetic cation-exchange resin (MCER) was prepared by copolymerization of oleic acid-grafted magnetite with styrene, divinylbenzene (DVB), and triallylisocyanurate (TAIC) for removing Cd(II) from wastewater. A non-magnetic cation-exchange polystyrene resin (CEPR) was also prepared as a reference. Structural and morphological analyses revealed that the MCER and CEPR were mesoporous microspheres; the MCER contained about 25% Fe3O4. The influence of temperature, pH, contact time, and the initial concentration of Cd(II) on the adsorption of Cd(II) was investigated. The maximum adsorption capacity of the MCER reached 88.56 mg/g, which was achieved at 343 K using a Cd(II) initial concentration of 200 mg/L. The adsorption processes attained equilibrium within 120 min for the MCER and 300 min for the CEPR, and were well described by a pseudo-second-order kinetic model. Furthermore, the equilibrium adsorption data fitted the Freundlich isotherm model better than the Langmuir model. The superior magnetic response and regeneration of the MCER make it a good candidate as an adsorbent for removing Cd(II) from wastewater.


Assuntos
Cádmio/química , Resinas de Troca de Cátion/química , Poliestirenos/química , Águas Residuárias/química , Poluentes Químicos da Água/química , Adsorção , Cátions/análise , Óxido Ferroso-Férrico , Concentração de Íons de Hidrogênio , Cinética , Temperatura , Purificação da Água/métodos
10.
Mol Imaging Biol ; 20(6): 1008-1014, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-29687322

RESUMO

PURPOSE: The aim of this study was to optimize a radiolabeling method using cationic processed Ga-68 eluates from a SnO2-based 68Ge/68Ga generator, followed by the development of DOTA-Tyr3-Thre8-octreotide (DOTATATE) kits. PROCEDURES: Diluted generator eluates were adsorbed on a SCX resin and desorbed with acidified 5 M NaCl solution. Optimized labeling conditions were determined by variation of pH, using 35 µg DOTATATE and sodium acetate buffer. DOTATATE kits were developed based on optimized radiolabeling conditions, were labeled, and evaluated. RESULTS: Optimized labeling conditions resulted in a radiolabeling efficiency of around 99 % and radiochemical yield of almost 85 %. Different kit preparation methods did not significantly influence the radiolabeling results. Kits were found to be stable over 3 months. CONCLUSION: A labeling method using SCX-processed Ga-68 eluates was optimized. DOTATATE kits specifically for these SCX-processed Ga-68 eluates were successfully formulated. A post-labeling Sep-Pak C18 purification should be optional.


Assuntos
Resinas de Troca de Cátion/química , Radioisótopos de Gálio/química , Germânio/química , Compostos Organometálicos/química , Radioquímica/métodos , Radioisótopos/química , Compostos de Estanho/química , Coloides/química , Concentração de Íons de Hidrogênio , Peptídeos/química , Acetato de Sódio/química
11.
Bioelectrochemistry ; 121: 176-184, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29459302

RESUMO

Microbial desalination cell (MDC) is a bioelectrochemical system capable of oxidizing organics, generating electricity, while reducing the salinity content of brine streams. As it is designed, anion and cation exchange membranes play an important role on the selective removal of ions from the desalination chamber. In this work, sulfonated sodium (Na+) poly(ether ether ketone) (SPEEK) cation exchange membranes (CEM) were tested in combination with quaternary ammonium chloride poly(2,6-dimethyl 1,4-phenylene oxide) (QAPPO) anion exchange membrane (AEM). Non-patterned and patterned (varying topographical features) CEMs were investigated and assessed in this work. The results were contrasted against a commercially available CEM. This work used real seawater from the Pacific Ocean in the desalination chamber. The results displayed a high desalination rate and power generation for all the membranes, with a maximum of 78.6±2.0% in salinity reduction and 235±7mWm-2 in power generation for the MDCs with the SPEEK CEM. Desalination rate and power generation achieved are higher with synthesized SPEEK membranes when compared with an available commercial CEM. An optimized combination of these types of membranes substantially improves the performances of MDC, making the system more suitable for real applications.


Assuntos
Fontes de Energia Bioelétrica/microbiologia , Cetonas/química , Polietilenoglicóis/química , Salinidade , Sais/isolamento & purificação , Água do Mar/análise , Sulfonas/química , Benzofenonas , Resinas de Troca de Cátion/química , Eletricidade , Eletrodos , Desenho de Equipamento , Membranas Artificiais , Polímeros
12.
J AOAC Int ; 100(2): 560-565, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28118575

RESUMO

Sensitive detection of heavy metal ions in water is of great importance considering the effects that heavy metals have on public health. A developed fluidized bed enrichment technique was used to concentrate and detect low concentrations of Cu2+, Co2+, and Ni2+ in water samples by near-IR diffuse reflectance (NIDR) spectroscopy (NIDRS) directly without using any chemicals or reagents. The NIDR spectra of adsorbent were measured on-line, and quantitative detection was achieved by applying a built partial least-squares chemometric model. Sensitivity and accuracy was improved significantly because large-volume mixture solutions were used in the enrichment process. Root mean square error of cross-validation values for Cu2+, Co2+, and Ni2+ were 0.29, 0.41, and 0.35 µg/mL, respectively, with mean relative error values in the acceptable range of 6.56-10.27%. This study confirms the potential application of fluidized bed enrichment combined with NIDRS and chemometrics for the simultaneous detection of trace heavy metal ions in water, with low relative error.


Assuntos
Cobalto/análise , Cobre/análise , Análise dos Mínimos Quadrados , Níquel/análise , Poluentes Químicos da Água/análise , Resinas de Troca de Cátion/química , Cátions Bivalentes , Concentração de Íons de Hidrogênio , Espectroscopia de Luz Próxima ao Infravermelho , Água/química
13.
J Chromatogr A ; 1440: 1-14, 2016 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-26896921

RESUMO

A facile synthesis of an ion exchange material (FSG-PAN) has been achieved by functionalizing silica gel with an azo-dye. Its composition and structure are well assessed by systematic analysis. Extractor possesses high BET surface area (617.794m(2)g(-1)), exchange capacity and break-through capacity (BTC) (Q0 Zn(II): 225; Cd(II): 918; Hg(II): 384, Cu(II): 269 and Co(II): 388µMg(-1)). The sorption process was endothermic (+ΔH), entropy-gaining (+ΔS) and spontaneous (-ΔG) in nature. Preconcentration factor has been optimized at 172(Zn(II)); 157.2(Cd(II)); 193.6(Hg(II)); 176(Cu(II)); 172.4(Co(II)). Density functional theory calculation has been performed to analyze the sorption pathway. BTC (µMg(-1)) of FSG-PAN was found to be the product of its frontier orbitals and state of sorbed metal ion species, x (at x=1, mononuclear and x>1, a polynuclear species; i.e., BTC=[amount of HOMO]×x). FSG-PAN is used for the selective separation and preconcentration of Zn(II), Cd(II), Hg(II), Cu(II),Co(II) from large volume sample (800mL) of low concentration (0.017-0.40mML(-1)) in presence of foreign ions (50-300mML(-1)) at optimum conditions (pH: 7.0±1.5, flow rate: 2.5mLmin(-1), temperature: 27°C, equilibration-time: 5min). The method was found to be effective for real samples also.


Assuntos
Compostos Azo/química , Resinas de Troca de Cátion/química , Técnicas de Química Analítica/métodos , Troca Iônica , Metais Pesados/isolamento & purificação , Extração em Fase Sólida , Metais Pesados/química
15.
J Environ Manage ; 128: 822-7, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-23867839

RESUMO

Resin supported nanoscale zero-valent iron (R-nZVI) was synthesized by the borohydride reduction method. Batch experiments were conducted to evaluate the factors affecting Cr(VI) removal. It was found that nZVI loads, resin dose, pH value and initial concentration of Cr(VI) were all important factors. Scanning electron microscopy showed that the nZVI particles in R-nZVI became sphere after reacting with Cr(VI). This phenomenon was attributed to the co-precipitation of Cr(III) and Fe(III) on the surface of resin. X-ray diffraction pattern confirmed that Fe(0) diminished after the reaction. At optimum conditions, the Cr(VI) removal efficiency was 84.4% when the initial concentration of Cr(VI) was 20.0 mg/L. Regeneration of R-nZVI and resin was possible. R-nZVI can also remove Cr(III) efficiently. However, the removal mechanisms of Cr(VI) (anion) and Cr(III) (cation) are different. The former is chemical reduction, while the latter is ion exchange at pH below 6.3 and precipitation at pH above 6.3. This study demonstrates that R-nZVI has the potential to become an effective agent for treating wastewater containing Cr(VI) and Cr(III).


Assuntos
Cromo/isolamento & purificação , Ferro/química , Nanopartículas Metálicas , Poluentes Químicos da Água/isolamento & purificação , Resinas de Troca de Cátion/química , Concentração de Íons de Hidrogênio , Cinética , Microscopia Eletrônica de Varredura , Reciclagem , Eliminação de Resíduos Líquidos/métodos , Difração de Raios X
16.
J Proteome Res ; 12(7): 3277-87, 2013 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-23745983

RESUMO

Protein N-terminal acetylation is one of the most common modifications occurring co- and post-translationally on either eukaryote or prokaryote proteins. However, compared to other protein modifications, the physiological role of protein N-terminal acetylation is relatively unclear. To explore the biological functions of protein N-terminal acetylation, a robust and large-scale method for qualitative and quantitative analysis of this modification is required. Enrichment of N(α)-acetylated peptides or depletion of the free N-terminal and internal tryptic peptides prior to analysis by mass spectrometry are necessary based on current technologies. This study demonstrated a simple strong cation exchange (SCX) fractionation method to selectively enrich N(α)-acetylated tryptic peptides via dimethyl labeling without the need for tedious protective labeling and depleting procedures. This method was introduced for the comprehensive analysis of N-terminal acetylated proteins from HepG2 cells. Several hundred N-terminal acetylation sites were readily identified in a single SCX flow-through fraction. Moreover, the N(α)-acetylated peptides of some protein isoforms were simultaneously observed in the SCX flow-through fraction, which indicated that this approach can be utilized to discriminate protein isoforms with very similar full sequences but different N-terminal sequences, such as ß-actin/γ-actin, ERK1/ERK2, α-centractin/ß-centractin, and ADP/ATP translocase 2 and 3. Compared to other methods, this method is relatively simple and can be directly implemented in a two-dimensional separation (SCX-RP)-mass spectrometry scheme for quantitative N-terminal proteomics using stable-isotope dimethyl labeling.


Assuntos
Resinas de Troca de Cátion/química , Peptídeos/isolamento & purificação , Processamento de Proteína Pós-Traducional , Proteínas/isolamento & purificação , Acetilação , Células Hep G2 , Humanos , Marcação por Isótopo , Peptídeos/química , Proteínas/química , Proteômica/métodos , Espectrometria de Massas em Tandem
17.
J Sep Sci ; 36(14): 2231-43, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23712935

RESUMO

In the present study, three types of silica-based monoliths, i.e. the first and second generations of commercial silica monolithic columns and a wide-pore prototype monolith were compared for the analysis of large biomolecules. These molecules possess molecular weights between 1 and 66 kDa. The gradient kinetic performance of the first-generation monolith was lower than that of the second generation, for large biomolecules (>14 kDa) but very close with smaller ones (1.3-5.8 kDa). In contrast, the wide-pore prototype column was particularly attractive with proteins larger than 19 kDa (higher peak capacity). Among these three columns, the selectivity and retention remained quite similar but a possible larger number of accessible and charged residual silanols was noticed on the wide-pore prototype material, which led to unpredicted small changes in selectivity and slightly broader peaks than expected. The peak shapes attained with the addition of 0.1% formic acid in the mobile phase remained acceptable for MS coupling, particularly for biomolecules of less than 6 kDa. It was found that one of the major issues with all of these silica-based monoliths is the possible poor recovery of large biomolecules (principally with monoclonal antibody fragments of more than 25 kDa).


Assuntos
Resinas de Troca de Cátion/química , Cromatografia por Troca Iônica/instrumentação , Peptídeos/isolamento & purificação , Proteínas/isolamento & purificação , Dióxido de Silício/química , Adsorção , Cromatografia por Troca Iônica/métodos , Peso Molecular , Peptídeos/química , Porosidade , Proteínas/química
18.
J Environ Manage ; 124: 156-64, 2013 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-23623032

RESUMO

Increasing environmental awareness is being urged for the safe disposal of (226)Ra-contaminated production water generated in the oil industry. Birnessite, antimony silicate and their cationic derivatives were studied for the take-up of (226)Ra using the batch-type method under experimentally determined parameters, viz. contact time, solution-solid ratio and (226)Ra concentration. Data was expressed in terms of distribution coefficients. Sorption experiments were performed in different concentrations of nitric acid in order to speculate the mechanism of (226)Ra uptake. Variation in the magnitude of sorption efficiency of the materials in the presence of the major components of waste streams, i.e. Na(+), K(+) and Ca(2+), revealed that K(+) was the greatest competitor and Na(+) the least. The application of the materials to sorb (226)Ra from actual oil co-production water samples, collected from Der Ezzor and Al Fourat petroleum companies (DEZPC and AFPC), was interpreted in terms of the exchange properties of the materials and water characterisation. Of the parameters studied, the selectivity of materials was shown to be greatly dependent on the pH of wastewater to be treated.


Assuntos
Resinas de Troca de Cátion/química , Óleos/química , Rádio (Elemento)/química , Óxido Nítrico/química , Difração de Pó
19.
J Hazard Mater ; 248-249: 59-68, 2013 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-23353931

RESUMO

2-Amino-6-nitro-benzothiazole and thiosemicarbazide with formaldehyde (BTF) terpolymer was synthesized by the condensation polymerization technique. The elemental analysis and physico-chemical parameters of the terpolymer were measured. This chelation terpolymer was characterized by infrared, electronic and nuclear magnetic resonance ((1)H &(13)C NMR) spectral studies. The molecular weight of the terpolymer was determined by gel permeation chromatography (GPC). Surface analysis of the terpolymer was analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) method. The thermal stability of the terpolymer was analyzed by thermogravimetric analysis (TGA). The cation-exchange property of the terpolymer was determined by batch equilibrium method with the effect of pH, contact time and electrolytes. The reusability of the resin was also studied to estimate the effectiveness of the terpolymer resin.


Assuntos
Benzotiazóis/química , Resinas de Troca de Cátion/química , Formaldeído/química , Polímeros/química , Semicarbazidas/química , Cátions , Troca Iônica , Espectroscopia de Ressonância Magnética , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria , Difração de Raios X
20.
Recent Results Cancer Res ; 194: 33-42, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-22918753

RESUMO

New (68)Ge/(68)Ga radionuclide generators provide the positron emitter (68)Ga (T½ = 67.7 min) as an easily available and relatively inexpensive source of a PET nuclide for labeling of interesting targeting vectors. However, currently available "ionic" (68)Ge/(68)Ga radionuclide generators are not necessarily optimized for the routine synthesis of (68)Ga-labeled radiopharmaceuticals in a clinical environment. Post-processing of (68)Ge/(68)Ga generators using cation exchange resins provides chemically and radiochemically pure (68)Ga with 97±2% within less than 4 min, with (68)Ge almost completely removed, and ready for online labeling. This simple, fast, and efficient technology can be extended for new applications. The options are (a) to transfer (68)Ga from the cation exchange resin onto an anion exchange resin, to remove acetone, and to further purify the (68)Ga, (b) to obtain (68)Ga in pure non-aqueous solution via (68)Ga(acac)(3) as a synthon for syntheses in organic solvents, and (c) to create an option toward instantaneous determination of (68)Ge breakthrough, what may be required prior to the release of (68)Ga radiopharmaceutical preparations.


Assuntos
Resinas de Troca de Cátion/química , Radioisótopos de Gálio/isolamento & purificação , Geradores de Radionuclídeos , Compostos Radiofarmacêuticos/síntese química
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