Matrix‐assisted laser desorption/ionization mass spectrometry of polysaccharides

Garrozzo, Domenico; Impallomeni, Giuseppe; Spina, Emanuela; Sturiale, Luisa; Zanetti, Flavio

doi:10.1002/rcm.1290091014

Cited by 112 publications

(86 citation statements)

References 14 publications

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“…MALDI can substantially underestimate the molecular weight of polysaccharides because oligosaccharides suppress the ionization and desorption of larger saccharides (26). Thus, the MALDI data may represent oligomers resulting from the degradation of the THF during storage.…”

Section: Thf Isolated From U Ceramboides Is Highly Active and Contaimentioning

confidence: 99%

A nonprotein thermal hysteresis-producing xylomannan antifreeze in the freeze-tolerant Alaskan beetle Upis ceramboides

Walters¹,

Serianni

Sformo

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

100

117

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Thermal hysteresis (TH), a difference between the melting and freezing points of a solution that is indicative of the presence of large-molecular-mass antifreezes (e.g., antifreeze proteins), has been described in animals, plants, bacteria, and fungi. Although all previously described TH-producing biomolecules are proteins, most thermal hysteresis factors (THFs) have not yet been structurally characterized, and none have been characterized from a freeze-tolerant animal. We isolated a highly active THF from the freeze-tolerant beetle, Upis ceramboides, by means of ice affinity. Amino acid chromatographic analysis, polyacrylamide gel electrophoresis, UV-Vis spectrophotometry, and NMR spectroscopy indicated that the THF contained little or no protein, yet it produced 3.7 ؎ 0.3°C of TH at 5 mg/ml, comparable to that of the most active insect antifreeze proteins. Compositional and structural analyses indicated that this antifreeze contains a ␤-mannopyranosyl-(134) ␤-xylopyranose backbone and a fatty acid component, although the lipid may not be covalently linked to the saccharide. Consistent with the proposed structure, treatment with endo-␤-(134)xylanase ablated TH activity. This xylomannan is the first TH-producing antifreeze isolated from a freeze-tolerant animal and the first in a new class of highly active THFs that contain little or no protein.antifreeze protein ͉ insect cold tolerance ͉ glycolipid ͉ membrane associated antifreeze

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Section: Thf Isolated From U Ceramboides Is Highly Active and Contaimentioning

confidence: 99%

A nonprotein thermal hysteresis-producing xylomannan antifreeze in the freeze-tolerant Alaskan beetle Upis ceramboides

Walters¹,

Serianni

Sformo

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

100

117

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“…17 A significant improvement in agreement between the two techniques was reported when the polydispersity of polysaccharide samples was reduced by fractionation, using preparative SEC prior to MALDI-TOFMS. 18 Despite these ongoing efforts, major problems remain before findings outlined above can be translated into a coherent method to obtain quantitative molecular mass distributions of coal derived samples. In this paper we report on variations in MM-distribution observed by MALDI-TOFMS as a function of two techniquerelated parameters: the ion accelerating voltage and the composition of the matrix used to assist ionization.…”

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confidence: 99%

Choice of Extraction Voltage and Matrix in the Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry of Coal Tar Pitch — Pyridine Insolubles

Domin

Moreea

Lázaro

et al. 1997

Rapid Commun. Mass Spectrom.

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Variations in molecular mass distributions observed by matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry as a function of changes in the ion accelerating voltage and composition of the matrix have been investigated, using the pyridine-insoluble fraction of a coal tar pitch. With increasing ion extraction voltages (10, 20 and 30 kV) and in the absence of added matrix, spectra clearly showed increases in intensity, particularly at higher masses. The use of higher ion extraction voltages may be considered as providing a more complete inventory of ionized species, apparently significantly enhancing the kinetic energy imparted to larger molecular weight materials. Magnitudes of molecular masses at maximum ion intensity observed using a set of different matrices may be ordered as follows: m/z 1500 [dimethoxy-4-hydroxycinnamic (sinapinic) acid], m/z 1400 (2,5-dihydroxybenzoic acid), m/z 900 [2-(4-hydroxyphenylazo)-benzoic acid], m/z 900 (α-cyano-3-hydroxycinnamic acid), m/z 300 (9-anthracenecarboxylic acid) and m/z 300 (no matrix and a sample loading comparable with the with-matrix experiments). Maximum ion intensities, in the absence of matrix, were found at values which varied from about 300 m/z up to about m/z 1500 as sample loading varied from very low (i.e. suitable for with-matrix operation) up to a visibly black spot. In the absence of a quantitatively based criterion for distinguishing between signal and instrument noise at high mass, accurate high mass limits were not available. However, in each case, ion signals could clearly be observed at values greater than m/z 100 000. The present MALDI spectra do not necessarily show the highest molecular mass materials present in the sample. In view of the observed changes in the spectra with ion extraction voltage and matrix composition, it seems conceivable that higher voltages and/or specific matrices, other than those used in the study, may lead to the detection of larger molecules. © 1997 by John Wiley & Sons, Ltd. Received 23 December 1996; Revised 3 February 1997; Accepted 25 February 1997 Rapid. Commun. Mass Spectrom. 11, 638-645 (1997 Characterization by laser desorption mass spectrometry has considerably extended the range of molecular masses identified in coal-derived liquids. The work was initially undertaken in an attempt to provide independent confirmation for the identification of molecular masses (MMs) up to 4-6000 Da found by size-exclusion chromatography (SEC).1-5 During this preliminary stage of the study, MMs up to the limit of a LIMA (laser ionization mass analysis) instrument (m/z 12 000) were detected in liquefaction extracts and in a coal tar pitch. [6][7][8][9] In these experiments, the reflectron flight path caused loss of detection at high mass but the instrument could not be operated in linear mode. Experiments were conducted at an ion extraction voltage of 20 kV and with a defocused primary beam to prevent the breaking up of sample molecules due to the power of the laser. However, lacking a spectrum additio...

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“…Preferential desorption and ionisation of smaller-MM components by MALDI-MS has been proposed as a likely explanation, 7 and recently demonstrated using polystyrene molecular mass standards.…”

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confidence: 99%

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of kerogen extracts: effect of interactions between sample structure and matrix

Herod

Lázaro

Rahman

et al. 1997

Rapid Commun. Mass Spectrom.

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This paper describes experiments carried out within the framework of examining capabilities of MALDI-TOF-MS in the characterisation of fossil fuels and related materials. The work has focused on the effect of interactions between sample structure and matrix composition on the quality of MALDI spectra. Solvent extracts from six kerogens have been examined by MALDI-MS in the presence of three matrices of different composition and in the absence of matrix (laser ablation). The kerogen extracts have also been characterised by size exclusion chromatography (SEC) and UV-fluorescence spectroscopy (UV-F). In the presence of the three matrices (sinapinic acid, 2,5-dihydroxybenzoic acid and α-cyano-3-hydroxycinnamic acid), spectra of extracts from the three geologically 'younger' kerogens showed larger molecular mass distributions compared to spectra of extracts from the corresponding 'older' kerogens. This result directly contradicted trends observed in the absence of matrix, where extracts from 'older' kerogens showed larger molecular mass distributions. Results from SEC and UV-F agreed with trends observed in MALDI-spectra acquired in the presence of matrix, particularly sinapinic acid. By contrast, we recently reported that high mass signal in laser ablation mass spectra of the pyridine-insoluble fraction of a coal tar pitch, obtained in the absence of matrix, closely matched signals obtained in the presence of sinapinic acid. Compared to the highly condensed aromatic structure of the coal tar pitch, the kerogen extracts (of considerably higher oxygen content) appear less able to readily absorb incident laser radiation (337 nm) in the absence of externally added matrix. The argument is consistent with apparently more efficient absorption of incident laser radiation by the geologically 'older' samples, when no matrix was used. Structural characteristics suggest that the geologically 'older' samples would be better able to act as 'self-matrix'. Thus, differences in structure and composition of the samples appear to go some way towards explaining differences between trends observed in the presence/absence of matrix. Dependence of MALDI spectra on molecular structure has also been found for two sets of biomass derived samples. Considerably more work appears warranted to determine MALDI-MS parameters appropriate to the analysis of the more oxygenated, lower rank, samples. Recently, 1,2 we described changes in the MALDI-TOF mass spectra of coal derived liquids as a function of changes in (i) ion extraction voltage, (ii) laser power (iii) matrix composition and (iv) sample deposition density. Increasing ion extraction voltages helps provide a more complete inventory of species already ionised, without otherwise disturbing the sample. It would appear advantageous, therefore, to use the highest possible values of the extraction voltage, apparently irrespective of other experimental parameters. Clearly, the upper limit of the ion extraction voltage is determined by the capabilities of installed hardware. We have, to date, been a...

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Matrix‐assisted laser desorption/ionization mass spectrometry of polysaccharides

Cited by 112 publications

References 14 publications

A nonprotein thermal hysteresis-producing xylomannan antifreeze in the freeze-tolerant Alaskan beetle Upis ceramboides

A nonprotein thermal hysteresis-producing xylomannan antifreeze in the freeze-tolerant Alaskan beetle Upis ceramboides

Choice of Extraction Voltage and Matrix in the Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry of Coal Tar Pitch — Pyridine Insolubles

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of kerogen extracts: effect of interactions between sample structure and matrix

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