The aim of this article is to study the modification of an inner capillary wall with sol-gel coating (pure silica sol-gel or silica sol-gel containing porphyrin-brucine conjugate) and determine its influence on the separation process using capillary electrophoresis/electrochromatography method. After modification of the inner capillary surface the separation of analytes was performed using two different phosphate buffers (pH 2.5 and 9.0) and finally the changes in electrophoretic mobilities of various samples were calculated. To confirm that the modification of the inner capillary surface was successful, the parts of the inner surfaces of capillaries were observed using scanning electron microscopy. The analytes used as testing samples were oligopeptides, nucleosides, nucleobases and finally nucleotides.
- Klíčová slova
- Capillary electrochromatography (CEC), Nucleo-compounds, Oligopeptides, Open-tubular capillary electrochromatography (OT-CEC), Porphyrin, Scanning electron microscopy (SEM), Sol–gel methods,
- MeSH
- chemické techniky analytické přístrojové vybavení metody MeSH
- kapilární elektrochromatografie * MeSH
- mikroskopie elektronová rastrovací MeSH
- nukleosidy izolace a purifikace MeSH
- nukleotidy izolace a purifikace MeSH
- oligopeptidy izolace a purifikace MeSH
- změna skupenství MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- nukleosidy MeSH
- nukleotidy MeSH
- oligopeptidy MeSH
Materials prepared on the base of bioactive silver compounds have become more and more popular due to low microbial resistance to silver. In the present work, the efficiency of polymethylmethacrylate (PMMA) thin films doped with silver ions, nanoparticles and silver-imidazole polymer complex was studied by a combination of AAS, XPS and AFM techniques. The biological activities of the proposed materials were discussed in view of the rate of silver releasing from the polymer matrix. Concentrations of Ag active form were estimated by its ability to interact with l-cysteine using electronic circular dichroism spectroscopy. Rates of the released silver were compared with the biological activity in dependence on the form of embedded silver. Antimicrobial properties of doped polymer films were studied using two bacterial strains: Staphylococcus epidermidis and Escherichia coli. It was found that PMMA films doped with Ag(+) had greater activity than those doped with nanoparticles and silver-imidazole polymeric complexes. However, the antimicrobial efficiency of Ag(+) doped films was only short-term. Contrary, the antimicrobial activity of silver-imidazole/PMMA films increased in time of sample soaking.
- Klíčová slova
- Antimicrobial properties, Doped polymer, Silver helical complex, Silver nanoparticles,
- MeSH
- antibakteriální látky chemie farmakologie MeSH
- cystein metabolismus MeSH
- Escherichia coli účinky léků MeSH
- imidazoly chemie farmakologie MeSH
- ionty chemie MeSH
- mikrobiální testy citlivosti metody MeSH
- nanočástice chemie MeSH
- polymery chemie MeSH
- polymethylmethakrylát chemie farmakologie MeSH
- sloučeniny stříbra chemie farmakologie MeSH
- Staphylococcus epidermidis účinky léků MeSH
- stříbro chemie farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- antibakteriální látky MeSH
- cystein MeSH
- imidazole MeSH Prohlížeč
- imidazoly MeSH
- ionty MeSH
- polymery MeSH
- polymethylmethakrylát MeSH
- sloučeniny stříbra MeSH
- stříbro MeSH
Three newly synthesized chiral selectors, namely, 2(I)-O-, 3(I)-O-, and 6(I)-O-carboxymethyl-γ-cyclodextrin, native γ-cyclodextrin, and commercially available carboxymethylated γ-cyclodextrin with degree of substitution of 3-6 were used as additives in a background electrolyte composed of phosphate buffer at 20 mmol/L concentration and pH 2.5. This system was used for the analysis of several biologically significant low-molecular-mass chiral compounds by capillary electrophoresis. The results confirmed that the position of carboxymethyl group influences the enantioseparation efficiency of all the studied analytes. The 2(I)-O- and 3(I)-O- regioisomers provide a significantly better resolution than native γ-cyclodextrin, while the 6(I)-O-regioisomer gives only a slightly better enantioseparation than native γ-cyclodextrin. The application of γ-cyclodextrin possessing higher number of carboxymethyl groups led to the best resolution for the majority of the compounds analyzed.
- Klíčová slova
- Capillary electrophoresis, Chiral separation, Enantioselectivity, Regioisomers, Substituted cyclodextrins,
- Publikační typ
- časopisecké články MeSH
CE represents a very powerful separation tool in the area of chiral separations. CD-mediated chiral CE is a continuously flourishing technique within the frame of the electromigration methods. In this review, a brief overview of the synthetic procedures leading to modified CDs is provided first. Next, selected aspects related to the utilization of CDs in chiral CE are discussed specifically in the view of recently published data. Advantages of CDs and basic principles of chiral CE are remained. The topic of the determination of binding constants is touched. Particular attention is paid to the effort aiming at better understanding of the molecular level of the enantiorecognition between CDs and the analyte in the solution. Powerful approaches extensively utilized in this field are NMR, molecular modeling, and computer simulations. Then, a summary of applications of CDs in the CE enantioseparations is given, covering years 2008-2013. Finally, the general trend of modified CDs use in separation science is statistically evaluated.
- Klíčová slova
- CD, CE, Chiral analysis, Enantioseparation, Synthesis,
- MeSH
- cyklodextriny * MeSH
- elektroforéza kapilární * přístrojové vybavení metody MeSH
- stereoizomerie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- cyklodextriny * MeSH
This work documents the influence of the position of single carboxymethyl group on the β-cyclodextrin skeleton on the enantioselectivity. These synthesized monosubstituted carboxymethyl cyclodextrin (CD) derivatives, native β-cyclodextrin, and commercially available carboxymethyl-β-cyclodextrin with degree of substitution approximately 3 were used as additives into the BGE consisting of phosphate buffer at 20 mmol/L concentration, pH 2.5, and several biologically significant low-molecular-mass chiral compounds were enantioseparated by CE. The results indicate that different substituent location on β-cyclodextrin skeleton has a significant influence on the enantioseparation of the investigated enantiomers. The enantioselectivity of 2(I)-O-regioisomer was better than with native β-cyclodextrin. Comparable results to native β-cyclodextrin were obtained for 6(I)-O- regioisomer and the enantioselectivity of 3(I)-O-regioisomer was even worse than with native β-cyclodextrin. Commercially available derivative of CD provides better resolutions than the monosubstituted carboxymethyl CD derivatives for most of the investigated analytes.
- Publikační typ
- časopisecké články MeSH
As an improvement on currently used methods of molecular spectroscopy, we used chiroptical techniques (electronic circular dichroism, fluorescence detected circular dichroism, and Raman optical activity [ROA]) to investigate the human blood plasma. To avoid the degradation of plasma samples, we measured them directly without any further preparation. We also tested cutoff weight filters (Amicon Ultra 100, 30, 10, and 3 kDa by Merck Millipore) to reduce undesirable fluorescence in the ROA and Raman spectra and also to remove the most abundant protein in the plasma-human serum albumin. The obtained spectra show that the ultrafiltration has a positive effect on undesirable fluorescence in ROA and Raman and also could reduce the amount of albumin in the plasma. Our results suggest that blood plasma can be successfully measured by the aforementioned methods. Therefore, these methods can potentially be useful for following research in the development of new, noninvasive, and reliable screening methods of clinical diagnostics.
- MeSH
- biochemická analýza krve metody MeSH
- lidé MeSH
- spektrální analýza metody MeSH
- stereoizomerie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The aim of this study was to characterize self-assembled structures of guanosine derivatives in aqueous solutions by vibrational circular dichroism (VCD) and electronic circular dichroism (ECD). Three guanosine derivatives were studied [5'-guanosine monophosphate (GMP), diphosphate (GDP), and triphosphate (GTP)] using a broad range of concentrations and various metal/guanosine ratios. VCD was used for the first time in this field and showed itself to be a powerful method for obtaining specific structural information in solution. It can also help to determine the impact that the cations have, when added to the solution, on the versatile structures of guanine derivatives in terms of their association and disassociation. Based on the markedly different intensities and signs of the VCD signals observed for different concentrations of guanosine derivatives, we propose various structures based on guanine quartets for high guanosine concentrations and high K(+)/guanosine ratios (i.e., columnar helical organization of the quartets, which are rearranged into a continuous helix). We performed a degenerate coupled oscillator (DCO) calculation to interpret the VCD spectra obtained and how they vary during the assembly of guanosine derivatives. The calculations correctly predicted the VCD spectra and enabled us to identify the structures of the metal cation/guanosine monophosphate aggregates. ECD in the ultraviolet region was used as a diagnostic tool to characterize the studied systems and as a contact point between the previously defined structures of the guanine derivative assemblies and the molecular systems studied here. These studies revealed that the VCD technique is a powerful new method for determining the structures of optically active guanosine motifs.
- MeSH
- cirkulární dichroismus metody MeSH
- G-kvadruplexy * MeSH
- guanosindifosfát chemie MeSH
- guanosintrifosfát chemie MeSH
- ionty chemie MeSH
- kyselina 5'-guanylová chemie MeSH
- molekulární konformace MeSH
- molekulární modely MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- guanosindifosfát MeSH
- guanosintrifosfát MeSH
- ionty MeSH
- kyselina 5'-guanylová MeSH
FTIR, circular dichroism (CD) and fluorescence spectroscopies were used to characterize conformational changes in horse liver alcohol dehydrogenase (HLADH) and ketoreductase (KRED 117) upon physical and covalent immobilizations on silica particles (functionalized with amino, epoxy and thiol groups) of different sizes. Conformational changes for immobilized enzymes were associated with high and low frequency shifts of the amide I and II bands. CD spectra of native HLADH and KRED 117 characterized with a negative peak at 222nm indicating a α-helical structure. The disappearance of the negative peak in the CD spectra of immobilized enzymes and appearance of a positive peak at 222nm supported these observations. These findings demonstrated unfolding of folded enzymes and exposure of the amino acid residues during denaturation with a red shift in tryptophan fluorescence. The decrease in specific activities (by 60-70% in all cases) for both immobilized enzymes was correlated to those of conformational changes. Silica-attached enzyme-NADH systems were evaluated for enantioselective reduction of 1-(p-methoxyphenyl)-propan-2-one. Conformational changes enhanced the enantioselectivity of immobilized HLADH with a switch in its stereoselectivity. In the case of immobilized KRED 117, kinetic values (V(max) and K(m)) were lower than that of the free enzyme, without enhancing enzyme enantio- and stereoselectivity.
- MeSH
- aldehydreduktasa MeSH
- aldo-keto reduktasy MeSH
- alkoholdehydrogenasa chemie MeSH
- alkoholoxidoreduktasy chemie MeSH
- cirkulární dichroismus MeSH
- enzymy imobilizované chemie MeSH
- fluorescenční spektrometrie MeSH
- játra enzymologie MeSH
- kinetika MeSH
- koenzymy chemie MeSH
- koně MeSH
- NAD chemie MeSH
- nanočástice chemie ultrastruktura MeSH
- oxid křemičitý chemie MeSH
- rozbalení proteinů MeSH
- sekundární struktura proteinů MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- stereoizomerie MeSH
- substrátová specifita MeSH
- terciární struktura proteinů MeSH
- tryptofan chemie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- aldehydreduktasa MeSH
- aldo-keto reduktasy MeSH
- alkoholdehydrogenasa MeSH
- alkoholoxidoreduktasy MeSH
- enzymy imobilizované MeSH
- koenzymy MeSH
- NAD MeSH
- oxid křemičitý MeSH
- tryptofan MeSH
The review article is devoted mainly to the description of applications of gold nanoparticles (GNPs) in separation sciences, especially in electromigration and chromatographic techniques. The applications of GNPs in particular separation methods, CE, microchip CE, MEKC, CEC, HPLC and GC, are classified according to the molecular size of the analytes from low-molecular-mass compounds via medium sized substances to biopolymers (proteins and nucleic acids). A very recent and promising utilization of GNPs for sample preparation, preconcentration and preseparation of selected analytes from complex matrices is presented as well. Moreover, in two introductory sections, typical preparation procedures of the GNPs and their modifications are presented and physico-chemical and analytical methods employed for characterization of the native and modified GNPs are briefly introduced.
- MeSH
- chemická frakcionace přístrojové vybavení metody MeSH
- chemické techniky analytické přístrojové vybavení metody MeSH
- chromatografie micelární elektrokinetická kapilární MeSH
- chromatografie plynová MeSH
- elektroforéza kapilární MeSH
- kovové nanočástice chemie MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- zlato * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- zlato * MeSH
This review summarizes recent developments in the area of porphyrin chemistry in the direction of biological applications. Novel synthetic methodologies are reviewed for porphyrin synthesis, porphyrin analog synthesis, stable porphyrinogens -- calixpyrroles, expanded porphyrins. Unique biological properties of those compounds are desribed with focus on photodynamic therapy (PDT) and molecular recognition properties. Special attentions given to metalloporphyrins with potential to affect heme degradation and CO formation.
- MeSH
- biologické modely MeSH
- fotochemoterapie * MeSH
- hem metabolismus MeSH
- oxid uhelnatý metabolismus MeSH
- porfyriny chemie terapeutické užití MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- hem MeSH
- oxid uhelnatý MeSH
- porfyriny MeSH
