The Experts below are selected from a list of 132 Experts worldwide ranked by ideXlab platform
Johan Haverkamp - One of the best experts on this subject based on the ideXlab platform.
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Loss of internal 1 → 6 substituted Monosaccharide Residues from underivatized and Per-O-methylated trisaccharides
Journal of the American Society for Mass Spectrometry, 1997Co-Authors: Lars P Brull, Johan Haverkamp, W Heerma, Vladimir Kovacik, Jane Thomas-oates, Pavol KovacAbstract:The fragmentation behavior of [M + H]+ ions of a series of underivatized and per-O-methylated trisaccharides having 1 → 6 linked Residues, of which one or two is a deoxy-fluoro or deoxy Residue and thus has a unique mass, has been studied by using collision-induced dissociation fast-atom bombardment mass spectrometry. In addition to the usual fragment ions resulting from glycosidic bond cleavage, fragment ions were observed which must have been generated following an unusual rearrangement process which can be rationalized in terms of the loss of an internal Monosaccharide Residue.
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loss of internal 1 6 substituted Monosaccharide Residues from underivatized and per o methylated trisaccharides
Journal of the American Society for Mass Spectrometry, 1997Co-Authors: Lars P Brull, Johan Haverkamp, W Heerma, Jane Thomasoates, Vladimir Kovacik, Pavol KovacAbstract:The fragmentation behavior of [M + H]+ ions of a series of underivatized and per-O-methylated trisaccharides having 1 → 6 linked Residues, of which one or two is a deoxy-fluoro or deoxy Residue and thus has a unique mass, has been studied by using collision-induced dissociation fast-atom bombardment mass spectrometry. In addition to the usual fragment ions resulting from glycosidic bond cleavage, fragment ions were observed which must have been generated following an unusual rearrangement process which can be rationalized in terms of the loss of an internal Monosaccharide Residue.
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oligosaccharide characterization using collision induced dissociation fast atom bombardment mass spectrometry evidence for internal Monosaccharide Residue loss
Journal of Mass Spectrometry, 1995Co-Authors: Vladimir Kovacik, W Heerma, Jane Thomasoates, Pavol Kovac, J. Hirsch, Johan HaverkampAbstract:The protonated and sodium cationized pseudomolecular ions of a series of reducing and non-reducing oligosaccharides possessing aldopentopyranosyl, 6-deoxyaldohexopyranosyl, ketohexofuranosyl, 4-O-methyl glucuronopyranosyl methyl ester and N-acetyl 2-deoxyglucopyranosylamine units were studied using collision-induced dissociation (CID) fast atom bombardment (FAB) mass spectrometry. The CID spectra of the [M + H]+ ions provide information about the sequence of the Monosaccharide units, while dissociation of the [M + Na]+ ions by two-bond ring cleavage processes gives rise to fragment ions which allow differentiation of 1 2 and 1 4 linkages. The influence of the structure of the constituent Monosaccharides on the dissociation of the [M + H]+ and [M + Na]+ ions is discussed. An unusual type of fragmentation, which we suggest involves the elimination of internal Monosaccharides Residues, has not only been observed in the FAB mass spectra but also in the unimolecular decomposition and CID spectra of both [M + H]+ ions and oxonium ions from several oligosaccharides containing Monosaccharide Residues with different masses.
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Oligosaccharide characterization using collision‐induced dissociation fast atom bombardment mass spectrometry: Evidence for internal Monosaccharide Residue loss
Journal of Mass Spectrometry, 1995Co-Authors: Vladimir Kovacik, W Heerma, Pavol Kovac, Jane Thomas-oates, J. Hirsch, Johan HaverkampAbstract:The protonated and sodium cationized pseudomolecular ions of a series of reducing and non-reducing oligosaccharides possessing aldopentopyranosyl, 6-deoxyaldohexopyranosyl, ketohexofuranosyl, 4-O-methyl glucuronopyranosyl methyl ester and N-acetyl 2-deoxyglucopyranosylamine units were studied using collision-induced dissociation (CID) fast atom bombardment (FAB) mass spectrometry. The CID spectra of the [M + H]+ ions provide information about the sequence of the Monosaccharide units, while dissociation of the [M + Na]+ ions by two-bond ring cleavage processes gives rise to fragment ions which allow differentiation of 1 2 and 1 4 linkages. The influence of the structure of the constituent Monosaccharides on the dissociation of the [M + H]+ and [M + Na]+ ions is discussed. An unusual type of fragmentation, which we suggest involves the elimination of internal Monosaccharides Residues, has not only been observed in the FAB mass spectra but also in the unimolecular decomposition and CID spectra of both [M + H]+ ions and oxonium ions from several oligosaccharides containing Monosaccharide Residues with different masses.
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Mass spectrometric discrimination between per‐O‐acetylated aldopentoses applied to an oligosaccharide
Rapid communications in mass spectrometry : RCM, 1993Co-Authors: Leonore Blok-tip, Wigger Heerma, Johan HaverkampAbstract:Unimolecular decomposition spectra of oxonium ions from peracetylated pentoses can be used for identification purposes. The fast-atom bombardment mass spectra of an oligosaccharide with a pentose Residue at the non-reducing terminus also contain this oxonium ion, which allows identification of this Monosaccharide Residue by a tandem mass spectrometry experiment. The applicability of this method is demonstrated using a xylopentaose.
Pavol Kovac - One of the best experts on this subject based on the ideXlab platform.
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Positive electrospray ion trap multistage mass spectrometric fragmentation of synthetic analogs of saccharide part of lipopolysaccharides of Vibrio cholerae O:1
Journal of The American Society for Mass Spectrometry, 2006Co-Authors: Vladimir Kovacik, Slavka Bekešová, Igor Tvaroška, Pavol KovacAbstract:Oligosaccharides (mono- to hexamers) that mimic the terminal epitopes of O-antigens of Vibrio cholerae O:1, serotypes Ogawa and Inaba, have been studied by electrospray ion trap (ESI IT) mass spectrometry. Sodium or potassium-cationized adducts are characteristic ions under the conditions of ESI-MS analysis. The tentative pathways of fragmentation have been proven by multistage ion trap MS (MS^n, n =1–3). The predominant pathway of fragmentation of the oligomers is the neutral loss of Monosaccharide Residue shortening the length of the oligosaccharide. In this way, conversion of the Ogawa to Inaba fragments takes place under the conditions of measurement. ESI MS/MS provided sufficient information about molecular mass, the number of saccharide Residues, and the structure of saccharides, about the C (4)-amide of 3-deoxy-L- glycero -tetronic acid (DGT) of the compounds investigated, and allows to distinguish between Ogawa and Inaba serotypes.
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loss of internal 1 6 substituted Monosaccharide Residues from underivatized and per o methylated trisaccharides
Journal of the American Society for Mass Spectrometry, 1997Co-Authors: Lars P Brull, Johan Haverkamp, W Heerma, Jane Thomasoates, Vladimir Kovacik, Pavol KovacAbstract:The fragmentation behavior of [M + H]+ ions of a series of underivatized and per-O-methylated trisaccharides having 1 → 6 linked Residues, of which one or two is a deoxy-fluoro or deoxy Residue and thus has a unique mass, has been studied by using collision-induced dissociation fast-atom bombardment mass spectrometry. In addition to the usual fragment ions resulting from glycosidic bond cleavage, fragment ions were observed which must have been generated following an unusual rearrangement process which can be rationalized in terms of the loss of an internal Monosaccharide Residue.
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Loss of internal 1 → 6 substituted Monosaccharide Residues from underivatized and Per-O-methylated trisaccharides
Journal of the American Society for Mass Spectrometry, 1997Co-Authors: Lars P Brull, Johan Haverkamp, W Heerma, Vladimir Kovacik, Jane Thomas-oates, Pavol KovacAbstract:The fragmentation behavior of [M + H]+ ions of a series of underivatized and per-O-methylated trisaccharides having 1 → 6 linked Residues, of which one or two is a deoxy-fluoro or deoxy Residue and thus has a unique mass, has been studied by using collision-induced dissociation fast-atom bombardment mass spectrometry. In addition to the usual fragment ions resulting from glycosidic bond cleavage, fragment ions were observed which must have been generated following an unusual rearrangement process which can be rationalized in terms of the loss of an internal Monosaccharide Residue.
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oligosaccharide characterization using collision induced dissociation fast atom bombardment mass spectrometry evidence for internal Monosaccharide Residue loss
Journal of Mass Spectrometry, 1995Co-Authors: Vladimir Kovacik, W Heerma, Jane Thomasoates, Pavol Kovac, J. Hirsch, Johan HaverkampAbstract:The protonated and sodium cationized pseudomolecular ions of a series of reducing and non-reducing oligosaccharides possessing aldopentopyranosyl, 6-deoxyaldohexopyranosyl, ketohexofuranosyl, 4-O-methyl glucuronopyranosyl methyl ester and N-acetyl 2-deoxyglucopyranosylamine units were studied using collision-induced dissociation (CID) fast atom bombardment (FAB) mass spectrometry. The CID spectra of the [M + H]+ ions provide information about the sequence of the Monosaccharide units, while dissociation of the [M + Na]+ ions by two-bond ring cleavage processes gives rise to fragment ions which allow differentiation of 1 2 and 1 4 linkages. The influence of the structure of the constituent Monosaccharides on the dissociation of the [M + H]+ and [M + Na]+ ions is discussed. An unusual type of fragmentation, which we suggest involves the elimination of internal Monosaccharides Residues, has not only been observed in the FAB mass spectra but also in the unimolecular decomposition and CID spectra of both [M + H]+ ions and oxonium ions from several oligosaccharides containing Monosaccharide Residues with different masses.
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Oligosaccharide characterization using collision‐induced dissociation fast atom bombardment mass spectrometry: Evidence for internal Monosaccharide Residue loss
Journal of Mass Spectrometry, 1995Co-Authors: Vladimir Kovacik, W Heerma, Pavol Kovac, Jane Thomas-oates, J. Hirsch, Johan HaverkampAbstract:The protonated and sodium cationized pseudomolecular ions of a series of reducing and non-reducing oligosaccharides possessing aldopentopyranosyl, 6-deoxyaldohexopyranosyl, ketohexofuranosyl, 4-O-methyl glucuronopyranosyl methyl ester and N-acetyl 2-deoxyglucopyranosylamine units were studied using collision-induced dissociation (CID) fast atom bombardment (FAB) mass spectrometry. The CID spectra of the [M + H]+ ions provide information about the sequence of the Monosaccharide units, while dissociation of the [M + Na]+ ions by two-bond ring cleavage processes gives rise to fragment ions which allow differentiation of 1 2 and 1 4 linkages. The influence of the structure of the constituent Monosaccharides on the dissociation of the [M + H]+ and [M + Na]+ ions is discussed. An unusual type of fragmentation, which we suggest involves the elimination of internal Monosaccharides Residues, has not only been observed in the FAB mass spectra but also in the unimolecular decomposition and CID spectra of both [M + H]+ ions and oxonium ions from several oligosaccharides containing Monosaccharide Residues with different masses.
Kazunori Kataoka - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of heterobifunctional poly(ethylene glycol) with a reducing Monosaccharide Residue at one end.
Bioconjugate chemistry, 1998Co-Authors: Teruo Nakamura, Yukio Nagasaki, Kazunori KataokaAbstract:A new synthetic method for a heterobifunctional poly(ethylene glycol) (PEG) having a Monosaccharide moiety at one end was created. PEG with a reducing Monosaccharide Residue at the α-end, which is linked to a defined position of the sugar molecule, could be prepared via the anionic polymerization of ethylene oxide (EO) initiated with a potassium alkolate of a protected Monosaccharide such as 1,2;5,6-di-O-isopropylidene-d-glucofuranose (DIGL), 1,2;3,4-di-O-isopropylidene-d-galactopyranose (DIGA), and 1,2-O-isopropylidene-3,5-O-benzylidene-d-glucofuranose (IBGL). The resulting PEGs possess the corresponding sugar molecule at the α-chain end and a hydroxyl group at the ω-chain end. The ω-chain end could be converted to several functional groups such as allyl, amino, and hydroxycarbonyl groups in high yield. Such heterobifunctional PEGs possessing a reducing Monosaccharide Residue at the α-end are one of the promising tools for bioconjugate chemistries.
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Synthesis of heterobifunctional poly(ethylene glycol) with a reducing Monosaccharide Residue at one end for drug delivery
Advanced Biomaterials in Biomedical Engineering and Drug Delivery Systems, 1996Co-Authors: Teruo Nakamura, Yukio Nagasaki, Masao Kato, Kazunori KataokaAbstract:Install of pilot molecules on surface of the micelle-forming polymeric drug is considered to further enhance cellular uptake of the micelle at target tissue. In order to achieve this strategy, new heterobifunctional poly(ethylene glycol) with a reducing Monosaccharide Residue at one end were synthesized. Potassium alkoxides of carbohydrate derivatives reacted with ethylene oxide(EO) to yield a variety of sugar derivative bearing poly(ethylene glycol). Subsequently, protective groups on carbohydrate Residue were removed to yield target compounds. Reducing Monosaccharide Residue was incorporated to one end of poly(ethylene glycol) chain regiospecifically and quantitatively without a spacer moiety.
Vladimir Kovacik - One of the best experts on this subject based on the ideXlab platform.
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Positive electrospray ion trap multistage mass spectrometric fragmentation of synthetic analogs of saccharide part of lipopolysaccharides of Vibrio cholerae O:1
Journal of The American Society for Mass Spectrometry, 2006Co-Authors: Vladimir Kovacik, Slavka Bekešová, Igor Tvaroška, Pavol KovacAbstract:Oligosaccharides (mono- to hexamers) that mimic the terminal epitopes of O-antigens of Vibrio cholerae O:1, serotypes Ogawa and Inaba, have been studied by electrospray ion trap (ESI IT) mass spectrometry. Sodium or potassium-cationized adducts are characteristic ions under the conditions of ESI-MS analysis. The tentative pathways of fragmentation have been proven by multistage ion trap MS (MS^n, n =1–3). The predominant pathway of fragmentation of the oligomers is the neutral loss of Monosaccharide Residue shortening the length of the oligosaccharide. In this way, conversion of the Ogawa to Inaba fragments takes place under the conditions of measurement. ESI MS/MS provided sufficient information about molecular mass, the number of saccharide Residues, and the structure of saccharides, about the C (4)-amide of 3-deoxy-L- glycero -tetronic acid (DGT) of the compounds investigated, and allows to distinguish between Ogawa and Inaba serotypes.
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loss of internal 1 6 substituted Monosaccharide Residues from underivatized and per o methylated trisaccharides
Journal of the American Society for Mass Spectrometry, 1997Co-Authors: Lars P Brull, Johan Haverkamp, W Heerma, Jane Thomasoates, Vladimir Kovacik, Pavol KovacAbstract:The fragmentation behavior of [M + H]+ ions of a series of underivatized and per-O-methylated trisaccharides having 1 → 6 linked Residues, of which one or two is a deoxy-fluoro or deoxy Residue and thus has a unique mass, has been studied by using collision-induced dissociation fast-atom bombardment mass spectrometry. In addition to the usual fragment ions resulting from glycosidic bond cleavage, fragment ions were observed which must have been generated following an unusual rearrangement process which can be rationalized in terms of the loss of an internal Monosaccharide Residue.
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Loss of internal 1 → 6 substituted Monosaccharide Residues from underivatized and Per-O-methylated trisaccharides
Journal of the American Society for Mass Spectrometry, 1997Co-Authors: Lars P Brull, Johan Haverkamp, W Heerma, Vladimir Kovacik, Jane Thomas-oates, Pavol KovacAbstract:The fragmentation behavior of [M + H]+ ions of a series of underivatized and per-O-methylated trisaccharides having 1 → 6 linked Residues, of which one or two is a deoxy-fluoro or deoxy Residue and thus has a unique mass, has been studied by using collision-induced dissociation fast-atom bombardment mass spectrometry. In addition to the usual fragment ions resulting from glycosidic bond cleavage, fragment ions were observed which must have been generated following an unusual rearrangement process which can be rationalized in terms of the loss of an internal Monosaccharide Residue.
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oligosaccharide characterization using collision induced dissociation fast atom bombardment mass spectrometry evidence for internal Monosaccharide Residue loss
Journal of Mass Spectrometry, 1995Co-Authors: Vladimir Kovacik, W Heerma, Jane Thomasoates, Pavol Kovac, J. Hirsch, Johan HaverkampAbstract:The protonated and sodium cationized pseudomolecular ions of a series of reducing and non-reducing oligosaccharides possessing aldopentopyranosyl, 6-deoxyaldohexopyranosyl, ketohexofuranosyl, 4-O-methyl glucuronopyranosyl methyl ester and N-acetyl 2-deoxyglucopyranosylamine units were studied using collision-induced dissociation (CID) fast atom bombardment (FAB) mass spectrometry. The CID spectra of the [M + H]+ ions provide information about the sequence of the Monosaccharide units, while dissociation of the [M + Na]+ ions by two-bond ring cleavage processes gives rise to fragment ions which allow differentiation of 1 2 and 1 4 linkages. The influence of the structure of the constituent Monosaccharides on the dissociation of the [M + H]+ and [M + Na]+ ions is discussed. An unusual type of fragmentation, which we suggest involves the elimination of internal Monosaccharides Residues, has not only been observed in the FAB mass spectra but also in the unimolecular decomposition and CID spectra of both [M + H]+ ions and oxonium ions from several oligosaccharides containing Monosaccharide Residues with different masses.
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Oligosaccharide characterization using collision‐induced dissociation fast atom bombardment mass spectrometry: Evidence for internal Monosaccharide Residue loss
Journal of Mass Spectrometry, 1995Co-Authors: Vladimir Kovacik, W Heerma, Pavol Kovac, Jane Thomas-oates, J. Hirsch, Johan HaverkampAbstract:The protonated and sodium cationized pseudomolecular ions of a series of reducing and non-reducing oligosaccharides possessing aldopentopyranosyl, 6-deoxyaldohexopyranosyl, ketohexofuranosyl, 4-O-methyl glucuronopyranosyl methyl ester and N-acetyl 2-deoxyglucopyranosylamine units were studied using collision-induced dissociation (CID) fast atom bombardment (FAB) mass spectrometry. The CID spectra of the [M + H]+ ions provide information about the sequence of the Monosaccharide units, while dissociation of the [M + Na]+ ions by two-bond ring cleavage processes gives rise to fragment ions which allow differentiation of 1 2 and 1 4 linkages. The influence of the structure of the constituent Monosaccharides on the dissociation of the [M + H]+ and [M + Na]+ ions is discussed. An unusual type of fragmentation, which we suggest involves the elimination of internal Monosaccharides Residues, has not only been observed in the FAB mass spectra but also in the unimolecular decomposition and CID spectra of both [M + H]+ ions and oxonium ions from several oligosaccharides containing Monosaccharide Residues with different masses.
Teruo Nakamura - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of heterobifunctional poly(ethylene glycol) with a reducing Monosaccharide Residue at one end.
Bioconjugate chemistry, 1998Co-Authors: Teruo Nakamura, Yukio Nagasaki, Kazunori KataokaAbstract:A new synthetic method for a heterobifunctional poly(ethylene glycol) (PEG) having a Monosaccharide moiety at one end was created. PEG with a reducing Monosaccharide Residue at the α-end, which is linked to a defined position of the sugar molecule, could be prepared via the anionic polymerization of ethylene oxide (EO) initiated with a potassium alkolate of a protected Monosaccharide such as 1,2;5,6-di-O-isopropylidene-d-glucofuranose (DIGL), 1,2;3,4-di-O-isopropylidene-d-galactopyranose (DIGA), and 1,2-O-isopropylidene-3,5-O-benzylidene-d-glucofuranose (IBGL). The resulting PEGs possess the corresponding sugar molecule at the α-chain end and a hydroxyl group at the ω-chain end. The ω-chain end could be converted to several functional groups such as allyl, amino, and hydroxycarbonyl groups in high yield. Such heterobifunctional PEGs possessing a reducing Monosaccharide Residue at the α-end are one of the promising tools for bioconjugate chemistries.
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Synthesis of heterobifunctional poly(ethylene glycol) with a reducing Monosaccharide Residue at one end for drug delivery
Advanced Biomaterials in Biomedical Engineering and Drug Delivery Systems, 1996Co-Authors: Teruo Nakamura, Yukio Nagasaki, Masao Kato, Kazunori KataokaAbstract:Install of pilot molecules on surface of the micelle-forming polymeric drug is considered to further enhance cellular uptake of the micelle at target tissue. In order to achieve this strategy, new heterobifunctional poly(ethylene glycol) with a reducing Monosaccharide Residue at one end were synthesized. Potassium alkoxides of carbohydrate derivatives reacted with ethylene oxide(EO) to yield a variety of sugar derivative bearing poly(ethylene glycol). Subsequently, protective groups on carbohydrate Residue were removed to yield target compounds. Reducing Monosaccharide Residue was incorporated to one end of poly(ethylene glycol) chain regiospecifically and quantitatively without a spacer moiety.