Human serum acid alpha-1-glycoprotein (AGP, orosomucoid) content of healthy individuals and cance... more Human serum acid alpha-1-glycoprotein (AGP, orosomucoid) content of healthy individuals and cancer patients was measured, isolated and purified using a protocol of fast and biocompatible sample preparation, ion exchange and dye-ligand affinity chromatographic methods. In comparison to the healthy individuals significantly higher serum AGP levels were found in a wide spectrum of cancer patients, indicating its diagnostic value in the malignant disease. Oligosaccharide content of AGP samples was separated following PNGase F enzyme digestion and analysed by RP-HPLC and MALDI-TOF mass spectrometry. RP-HPLC and MALDI-TOF mass spectrometric analysis of sugar constituents of AGP specimen originated from selected cancer patients with high serum AGP levels indicated the appearance of anomal distribution of bi-, tri- and tetra-antennary oligosaccharide structures compared to the healthy controls.
In this new convergent peptide synthetic approach the advantages of the Fmoc and Boc techniques a... more In this new convergent peptide synthetic approach the advantages of the Fmoc and Boc techniques are combined. Boc-protected peptide fragments prepared on 2-chlorotrityl resin by Fmoc-technique were coupled sequentially in solution. As an example, the C-terminal (91131) part of the ...
ChemInform Abstract Die Titelreaktion des Triarylmethylchlorids (I) ergibt sowohl in CH3OH als au... more ChemInform Abstract Die Titelreaktion des Triarylmethylchlorids (I) ergibt sowohl in CH3OH als auch in nicht-dissoziierenden Lösungsmitteln wie THF, Dioxan oder 1,2-Dimethoxy-ethan das Substitutionsprodukt (IIIa). Der Einsatz von CD3 ONa (IIb) lässt den teilweisen Austausch der p-Substituenten erkennen und führt in THF zu (IIIa)+(IIIb). Dieses vom Verhalten der Triphenylmethylhalogenide abweichende Ergebnis wird auf das Fehlen einer Ein-Elektronen-übertragung zurückgeführt. (Mechanismus).
The first results with the electron capture induced decomposition (ECID) method are presented in ... more The first results with the electron capture induced decomposition (ECID) method are presented in this paper in the case of the benzene doubly charged molecular ion. Several collision gases were used and it was determined that the ground-state C6H2+ ion is the precursor in all reaction channels, and the ground-state C6H6'+ ion is formed at threshold. Ions from rare gas targets were always formed in their ground states but ions from molecular targets could be formed in excited states as well. The internal energy distribution of the product C6H6" ion was determined by deconvolution of the ECID spectrum and the breakdown graph. An unexpected relationship was found between the ionization energy of the target and the mean internal energy of C&". Collisions on higher ionization energy targets resulted in higher internal energy C6H6'+ ions. Comparisons between the ECID and the mass spectra indicated the involvement of two isolated states in the fragmentation of benzene. Among other results a relationship was found between the translational energy release in ECID and the internal energy; collision cross sections were studied; and a new method for the determination of double ionization energies is suggested.
Cellular vesicles are membrane-enclosed organelles that transport material inside and outside the... more Cellular vesicles are membrane-enclosed organelles that transport material inside and outside the cell. Plant-derived vesicles are receiving increasing attention due to their potential as nanovectors for the delivery of biologically active substances. We aimed to expand our understanding about the heterogeneity and the protein biocargo of citrus fruit juice sac cell-derived vesicles. Micro-and nanosized vesicle fractions were isolated from four citrus species, C. sinensis, C. limon, C. paradisi and C. aurantium, characterized using physicochemical methods and protein cargos were compared using label-free quantitative shotgun proteomics. In each sample approximately 600-800 proteins were identified. Orthologues of most of the top-ranking proteins have previously been reported in extracellular vesicles of mammalian origin. Patellin-3-like, clathrin heavy chain, heat shock proteins, 14-3-3 protein, glyceraldehyde-3-phosphate dehydrogenase and fructose-bisphosphate aldolase 6 were highly expressed in all citrus vesicle fractions. The presence of membrane channel aquaporin on the other hand characteristic of the nanovesicle fractions. Bioinformatics revealed more than hundred protein orthologues potentially implicated in vesicular trafficking. In particular, CCV, COPI and COPII coat proteins indicates the presence of highly heterogeneous populations of intracellular transport vesicles. Moreover, the different hydrolases and oxidoreductases transported within the citrus fruitderived vesicles can be responsible for the various biological activities possessed by the preparations.
European Journal of Mass Spectrometry, Apr 1, 2019
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
The electron impact induced decomposition of the cis and trans isomeric pairs of five 1-trialkyls... more The electron impact induced decomposition of the cis and trans isomeric pairs of five 1-trialkylsilyl-2-alkoxycarbonylcyclopropanes were investigated. Compared with carbon analogues, the silicon atom inhibited ring opening and dramatically altered the fragmentation. The main primary decomposition routes were alkyl loss from silicon, and trialkylsilyl ion formation as well as trialkylalkoxysilane elimination. An unexpected inverse stereochemical effect was found for this latter reaction which was far less significant for the cis isomers, where the interacting SiQ3 and OR groups are close to each other, than for the trans isomers. This is explained by assuming a hidden silicon-oxygen bond formation, which is possible only in the cis isomers for geometric reasons. This interaction favours alkyl elimination over other fragmentations, and has a marked effect on the further decomposition of the [M-alkyl]' ions, where observed differences in abundance as great as three orders of magnitude are accounted for. spectra of 3 with a close derivative of its carbon analogue, 6 :
Rapid Communications in Mass Spectrometry, Aug 22, 2001
Microbial degradation processes play an important role in chemical water clearance taking place i... more Microbial degradation processes play an important role in chemical water clearance taking place in river sediments. Bacteria remove not only easily degradable organic species, but various xenobiotics as well, producing clear and xenobiotic free water for bank-filtered wells. Atrazine is a widely used herbicide, and it is one of the most common xenobiotics present in Danube water. In this study the pathway and kinetics of atrazine metabolism of sedimental microbiota were studied. Samples were collected from river sediment and from pure microbial growth cultures. An analytical scheme including sample preparation, chromatography and mass spectrometry was developed and optimised. Solid-phase extraction (SPE) was found to be satisfactory for sample preparation. For qualitative analysis of samples both reversed-phase and normal-phase high-performance liquid chromatography/mass spectrometry (HPLC/MS) methods were developed and used. Selectivity, detection limits and accuracy of the two methods were compared. Using this analytical scheme, the full atrazine metabolism of the organism Comamonas acidovorans was explored. Altogether, 12 metabolites were identified from the original compound to the urea end product. Detection limits in the range of 50 ng L À1 À1mg L À1 were obtained for different metabolites.
Quantum chemistry is used with increasing frequency for the evaluation and explanation of mass sp... more Quantum chemistry is used with increasing frequency for the evaluation and explanation of mass spectrometric characteristics. Here a short overview is given on the semiempirical and ab initio theoretical methods, their advantages and limitations. Beside energetics, various other parameters (geometry, bond order, energy partitioning, spin and charge density, free valence) can be used to characterise ion structures, reactions and possibly to predict fragmentation behaviour, and these are discussed in some detail. Three illustrative examples are given: description of a simple bond cleavage, discussion of differences between isomers and a calculation of kinetic energy release in charge separation processes.
Rapid Communications in Mass Spectrometry, Aug 1, 1992
The potential of conventional mass spectrometers in the synthesis of chemicals by ion/molecule re... more The potential of conventional mass spectrometers in the synthesis of chemicals by ion/molecule reactions is demonstrated by a collection of examples in different chemical fields.
Results of 16 different mass spectrometric ionization and sample-introduction methods are compare... more Results of 16 different mass spectrometric ionization and sample-introduction methods are compared for the case of a thermally very labile antibiotic, rifapentine. These suggest that extensive thermal decomposition occurs during evaporation when the sample can come into contact with hot metal parts, usually the source housing. The intensity of the molecular ion and the extent of fragmentation depend on various parameters, such as the ionization process, positive or negative-ion detection and the type of sample introduction. The most informative methods for rifapentine seem to be 'in-beam' electron impact, negative ionization with particle beam and direct liquid introduction interfaces and positive-and negative-ion fast atom bombardment.
Rapid Communications in Mass Spectrometry, Jul 1, 1993
The electron-impact induced decomposition of some spiroepoxides prepared from E-3-arylideneflavan... more The electron-impact induced decomposition of some spiroepoxides prepared from E-3-arylideneflavanones has been examined by means of low-and high-resolution mass spectrometry, mass-analysed ion kinetic energy (MIKE) spectrometry and collision-induced dissociation (CID) experiments. The compounds studied were found to undergo a rearrangement reaction resulting in a very intense odd-electron ion. The MIKE and CID-MIKE spectra of this type of ion generated from the unsubstituted epoxide proved to be identical to those of the molecular ion of trans-stilbene. The isomerization of epoxides to the corresponding carbonyl compounds prior to fragmentation was not observed.
The Central and Eastern European Proteomic Conference (CEEPC) proudly celebrated its 10th Anniver... more The Central and Eastern European Proteomic Conference (CEEPC) proudly celebrated its 10th Anniversary with an exciting scientific program inclusive of proteome, proteomics and systems biology in Budapest, Hungary. Since 2007, CEEPC has represented 'state-of the-art' proteomics in and around Central and Eastern Europe and these series of conferences have become a well-recognized event in the proteomic calendar. Fresher challenges and global healthcare issues such as ageing and chronic diseases are driving clinical and scientific research towards regenerative, reparative and personalized medicine. To this end, proteomics may enable diverse intertwining research fields to reach their end goals. CEEPC will endeavor to facilitate these goals.
Human serum acid alpha-1-glycoprotein (AGP, orosomucoid) content of healthy individuals and cance... more Human serum acid alpha-1-glycoprotein (AGP, orosomucoid) content of healthy individuals and cancer patients was measured, isolated and purified using a protocol of fast and biocompatible sample preparation, ion exchange and dye-ligand affinity chromatographic methods. In comparison to the healthy individuals significantly higher serum AGP levels were found in a wide spectrum of cancer patients, indicating its diagnostic value in the malignant disease. Oligosaccharide content of AGP samples was separated following PNGase F enzyme digestion and analysed by RP-HPLC and MALDI-TOF mass spectrometry. RP-HPLC and MALDI-TOF mass spectrometric analysis of sugar constituents of AGP specimen originated from selected cancer patients with high serum AGP levels indicated the appearance of anomal distribution of bi-, tri- and tetra-antennary oligosaccharide structures compared to the healthy controls.
In this new convergent peptide synthetic approach the advantages of the Fmoc and Boc techniques a... more In this new convergent peptide synthetic approach the advantages of the Fmoc and Boc techniques are combined. Boc-protected peptide fragments prepared on 2-chlorotrityl resin by Fmoc-technique were coupled sequentially in solution. As an example, the C-terminal (91131) part of the ...
ChemInform Abstract Die Titelreaktion des Triarylmethylchlorids (I) ergibt sowohl in CH3OH als au... more ChemInform Abstract Die Titelreaktion des Triarylmethylchlorids (I) ergibt sowohl in CH3OH als auch in nicht-dissoziierenden Lösungsmitteln wie THF, Dioxan oder 1,2-Dimethoxy-ethan das Substitutionsprodukt (IIIa). Der Einsatz von CD3 ONa (IIb) lässt den teilweisen Austausch der p-Substituenten erkennen und führt in THF zu (IIIa)+(IIIb). Dieses vom Verhalten der Triphenylmethylhalogenide abweichende Ergebnis wird auf das Fehlen einer Ein-Elektronen-übertragung zurückgeführt. (Mechanismus).
The first results with the electron capture induced decomposition (ECID) method are presented in ... more The first results with the electron capture induced decomposition (ECID) method are presented in this paper in the case of the benzene doubly charged molecular ion. Several collision gases were used and it was determined that the ground-state C6H2+ ion is the precursor in all reaction channels, and the ground-state C6H6'+ ion is formed at threshold. Ions from rare gas targets were always formed in their ground states but ions from molecular targets could be formed in excited states as well. The internal energy distribution of the product C6H6" ion was determined by deconvolution of the ECID spectrum and the breakdown graph. An unexpected relationship was found between the ionization energy of the target and the mean internal energy of C&". Collisions on higher ionization energy targets resulted in higher internal energy C6H6'+ ions. Comparisons between the ECID and the mass spectra indicated the involvement of two isolated states in the fragmentation of benzene. Among other results a relationship was found between the translational energy release in ECID and the internal energy; collision cross sections were studied; and a new method for the determination of double ionization energies is suggested.
Cellular vesicles are membrane-enclosed organelles that transport material inside and outside the... more Cellular vesicles are membrane-enclosed organelles that transport material inside and outside the cell. Plant-derived vesicles are receiving increasing attention due to their potential as nanovectors for the delivery of biologically active substances. We aimed to expand our understanding about the heterogeneity and the protein biocargo of citrus fruit juice sac cell-derived vesicles. Micro-and nanosized vesicle fractions were isolated from four citrus species, C. sinensis, C. limon, C. paradisi and C. aurantium, characterized using physicochemical methods and protein cargos were compared using label-free quantitative shotgun proteomics. In each sample approximately 600-800 proteins were identified. Orthologues of most of the top-ranking proteins have previously been reported in extracellular vesicles of mammalian origin. Patellin-3-like, clathrin heavy chain, heat shock proteins, 14-3-3 protein, glyceraldehyde-3-phosphate dehydrogenase and fructose-bisphosphate aldolase 6 were highly expressed in all citrus vesicle fractions. The presence of membrane channel aquaporin on the other hand characteristic of the nanovesicle fractions. Bioinformatics revealed more than hundred protein orthologues potentially implicated in vesicular trafficking. In particular, CCV, COPI and COPII coat proteins indicates the presence of highly heterogeneous populations of intracellular transport vesicles. Moreover, the different hydrolases and oxidoreductases transported within the citrus fruitderived vesicles can be responsible for the various biological activities possessed by the preparations.
European Journal of Mass Spectrometry, Apr 1, 2019
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
The electron impact induced decomposition of the cis and trans isomeric pairs of five 1-trialkyls... more The electron impact induced decomposition of the cis and trans isomeric pairs of five 1-trialkylsilyl-2-alkoxycarbonylcyclopropanes were investigated. Compared with carbon analogues, the silicon atom inhibited ring opening and dramatically altered the fragmentation. The main primary decomposition routes were alkyl loss from silicon, and trialkylsilyl ion formation as well as trialkylalkoxysilane elimination. An unexpected inverse stereochemical effect was found for this latter reaction which was far less significant for the cis isomers, where the interacting SiQ3 and OR groups are close to each other, than for the trans isomers. This is explained by assuming a hidden silicon-oxygen bond formation, which is possible only in the cis isomers for geometric reasons. This interaction favours alkyl elimination over other fragmentations, and has a marked effect on the further decomposition of the [M-alkyl]' ions, where observed differences in abundance as great as three orders of magnitude are accounted for. spectra of 3 with a close derivative of its carbon analogue, 6 :
Rapid Communications in Mass Spectrometry, Aug 22, 2001
Microbial degradation processes play an important role in chemical water clearance taking place i... more Microbial degradation processes play an important role in chemical water clearance taking place in river sediments. Bacteria remove not only easily degradable organic species, but various xenobiotics as well, producing clear and xenobiotic free water for bank-filtered wells. Atrazine is a widely used herbicide, and it is one of the most common xenobiotics present in Danube water. In this study the pathway and kinetics of atrazine metabolism of sedimental microbiota were studied. Samples were collected from river sediment and from pure microbial growth cultures. An analytical scheme including sample preparation, chromatography and mass spectrometry was developed and optimised. Solid-phase extraction (SPE) was found to be satisfactory for sample preparation. For qualitative analysis of samples both reversed-phase and normal-phase high-performance liquid chromatography/mass spectrometry (HPLC/MS) methods were developed and used. Selectivity, detection limits and accuracy of the two methods were compared. Using this analytical scheme, the full atrazine metabolism of the organism Comamonas acidovorans was explored. Altogether, 12 metabolites were identified from the original compound to the urea end product. Detection limits in the range of 50 ng L À1 À1mg L À1 were obtained for different metabolites.
Quantum chemistry is used with increasing frequency for the evaluation and explanation of mass sp... more Quantum chemistry is used with increasing frequency for the evaluation and explanation of mass spectrometric characteristics. Here a short overview is given on the semiempirical and ab initio theoretical methods, their advantages and limitations. Beside energetics, various other parameters (geometry, bond order, energy partitioning, spin and charge density, free valence) can be used to characterise ion structures, reactions and possibly to predict fragmentation behaviour, and these are discussed in some detail. Three illustrative examples are given: description of a simple bond cleavage, discussion of differences between isomers and a calculation of kinetic energy release in charge separation processes.
Rapid Communications in Mass Spectrometry, Aug 1, 1992
The potential of conventional mass spectrometers in the synthesis of chemicals by ion/molecule re... more The potential of conventional mass spectrometers in the synthesis of chemicals by ion/molecule reactions is demonstrated by a collection of examples in different chemical fields.
Results of 16 different mass spectrometric ionization and sample-introduction methods are compare... more Results of 16 different mass spectrometric ionization and sample-introduction methods are compared for the case of a thermally very labile antibiotic, rifapentine. These suggest that extensive thermal decomposition occurs during evaporation when the sample can come into contact with hot metal parts, usually the source housing. The intensity of the molecular ion and the extent of fragmentation depend on various parameters, such as the ionization process, positive or negative-ion detection and the type of sample introduction. The most informative methods for rifapentine seem to be 'in-beam' electron impact, negative ionization with particle beam and direct liquid introduction interfaces and positive-and negative-ion fast atom bombardment.
Rapid Communications in Mass Spectrometry, Jul 1, 1993
The electron-impact induced decomposition of some spiroepoxides prepared from E-3-arylideneflavan... more The electron-impact induced decomposition of some spiroepoxides prepared from E-3-arylideneflavanones has been examined by means of low-and high-resolution mass spectrometry, mass-analysed ion kinetic energy (MIKE) spectrometry and collision-induced dissociation (CID) experiments. The compounds studied were found to undergo a rearrangement reaction resulting in a very intense odd-electron ion. The MIKE and CID-MIKE spectra of this type of ion generated from the unsubstituted epoxide proved to be identical to those of the molecular ion of trans-stilbene. The isomerization of epoxides to the corresponding carbonyl compounds prior to fragmentation was not observed.
The Central and Eastern European Proteomic Conference (CEEPC) proudly celebrated its 10th Anniver... more The Central and Eastern European Proteomic Conference (CEEPC) proudly celebrated its 10th Anniversary with an exciting scientific program inclusive of proteome, proteomics and systems biology in Budapest, Hungary. Since 2007, CEEPC has represented 'state-of the-art' proteomics in and around Central and Eastern Europe and these series of conferences have become a well-recognized event in the proteomic calendar. Fresher challenges and global healthcare issues such as ageing and chronic diseases are driving clinical and scientific research towards regenerative, reparative and personalized medicine. To this end, proteomics may enable diverse intertwining research fields to reach their end goals. CEEPC will endeavor to facilitate these goals.
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Papers by Károly Vékey