Lactolation of β-Lactoglobulin Monitored by Electrospray Ionisation Mass Spectrometry

Morgan, François; Bouhallab, Saı̈d; Mollé, Daniel; Henry, Gwénaële; Maubois, Jean‐Louis; Léonil, Joëlle

doi:10.1016/s0958-6946(98)00025-9

Cited by 83 publications

(59 citation statements)

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“…Morgan et al [22] and Fenaille et al [24] observed that Lys residues at 47 and 91 were the first modified sites following dry-state lactosylation of bovine ␤-LG, although the rest of Lys residues were also glycated when longer incubation times were carried out.…”

Section: Lc-esi-ms Analysismentioning

confidence: 99%

Mass spectrometric characterization of glycated β-lactoglobulin peptides derived from galacto-oligosaccharides surviving the in vitro gastrointestinal digestion

Moreno

Quintanilla-López

Lebrón-Aguilar

et al. 2008

J. Am. Soc. Mass Spectrom.

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A mass spectrometric study has been carried out to elucidate the structures of glycated peptides obtained after in vitro gastrointestinal digestion of bovine {3-lactoglobulin ({3-LG) glycated with prebiotic galacto-oligosaccharides (GOS). The digests of both native and glycated {3-LG were analyzed by MALDI-MS, LC-ESI-MS, and LC-ESI-MS/MS. MALDI-MS profiles showed marked differences mainly related to the lower intensity of ions corresponding to the digest of glycated {3-LG. Overall, 58 and 23 unglycated peptides covering 97% and 63% of the mature {3-LG sequence could be identified in the digests of native and glycated samples, respectively. The LC-ESI-MS analyses corroborated the MALDI-MS results regarding the unglycated peptides but they also enabled an extensive investigation into the digest of glycated {3-LG. Thus, a total of 19 peptides glycated with GOS from two to seven hexose units could be identified. The tandem mass spectra of glycated peptides were mostly characterized by two neutral losses of 1026/1056, 864/894, 702/732, 540/570, 378/408, and 216/246 u, corresponding to the formation of the furylium ion and its subsequent "CHOH" loss, indicative of the peptide glycation with hepta-, hexa-, penta-, tetra-, tri-, and disaccharides, respectively. Also, other minor ionic species containing the furylium ring linked to different galactose units could be also detected, showing the diversity of the fragmentation pattern of peptides glycated with larger size carbohydrates. Finally, the putative GOS glycation sites could be determined at the NHz-terminal Leu residue and at Lys residues located in positions

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Section: Lc-esi-ms Analysismentioning

confidence: 99%

Mass spectrometric characterization of glycated β-lactoglobulin peptides derived from galacto-oligosaccharides surviving the in vitro gastrointestinal digestion

Moreno

Quintanilla-López

Lebrón-Aguilar

et al. 2008

J. Am. Soc. Mass Spectrom.

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“…Numerous published results have shown that EMR can progress with a very high rate in a powdered matrix with intermediate a w (0.3-0.7). Model studies on the solid-state EMR between the main whey protein, β-lactoglobulin (β-LG) and lactose have shown that the rate of Maillard reaction is accelerated at intermediate water activity and have provided a very extensive characterisation of glycoconjugates [13][14][15]. These studies demonstrated that extensively lactosylated β-LG -obtained after a dry heating (50 °C) of powder under a relative humidity of 65% -was more structurally stable than β-LG reacted with lactose in an aqueous solution.…”

Section: Introductionmentioning

confidence: 99%

Lactose crystallisation and early Maillard reaction in skim milk powder and whey protein concentrates

Morgan

Nouzille

Baechler

et al. 2005

Lait

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-Lactose crystallisation and Maillard reaction are two major modifications occurring in milk and whey powders during processing and storage. In this work, the aim was first to monitor the solid-state early Maillard reaction (EMR) in whey protein concentrates (WPC) heated at 60 °C and various water activities, and then, to characterise the physical changes that occur as a consequence of heat treatment in skim milk powder (SMP) and WPCs. After a w adjustment, SMP and WPC were heated at 60 °C in hermetic conditions to induce an amino-sugar reaction. Furosine analysis (% of blocked lysine) was used to monitor the progress of EMR. The results showed that the kinetic of EMR was linked to the initial a w of the powders. Heating of SMP may lead to the crystallisation of lactose in humidified powders, without apparently affecting the progress of EMR. Surprisingly, lactose crystallisation -monitored by micro-Differential Scanning Calorimetry -was easily induced in heated SMP, whereas it was delayed or even inhibited in WPC. The results showed that this effect was dependent on the protein/lactose ratio in WPCs.lactose crystallisation / early Maillard reaction / whey protein concentrate / water activity Résumé -Cristallisation du lactose et réaction de Maillard précoce dans les poudres de lait écrémé et les concentrés de protéines du lactosérum. La cristallisation du lactose et la réaction de Maillard sont deux modifications importantes survenant au cours de la production et du stockage des poudres de lait et de lactosérum. L'objectif de ce travail était dans un premier temps de suivre la réaction de Maillard précoce (RMP) dans des concentrés de protéines de lactosérum (CPL) chauffés à 60 °C à différentes activités d'eau et, dans un deuxième temps, de caractériser les modifications physiques consécutives au traitement thermique (comparaison poudres de lait écrémé et CPL). Les poudres de lait écrémé et les CPL -équilibrés à différentes activités d'eau -étaient chauffés à 60 °C dans des conditions hermétiques pour induire la RMP (suivie par l'analyse de la furosine). Les résultats indiquaient que la cinétique de la RMP était liée à l'activité d'eau initiale de poudres. Dans les poudres de lait écrémé humidifiées et chauffées, la cristallisation du lactose ne semblait pas avoir d'impact sur l'évolution de la RMP. La microcalorimétrie différentielle à balayage permettait d'observer que la cristallisation du lactose, induite facilement dans les poudres de lait écrémé, était retardée voire inhibée dans les CPL. Les résultats indiquent que cet effet était dépen-dant du rapport protéine/lactose dans les CPL. cristallisation du lactose / réaction de Maillard précoce / concentré de protéines du lactosérum / activité de l'eau

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“…Since the non-enzymatic lactosylation occurs at a temperature not significantly higher than the temperature of the cow practically all preparations of whey protein contain a certain fraction of lactosylated -Lg (Morgan et al, 1997(Morgan et al, , 1998, which has not been evidently revealed by the analytical methods previously used. Lactosylation might affect the biological as well as the functional properties of the protein.…”

Section: Introductionmentioning

confidence: 99%

“…Morgan and co-workers have shown that the N-terminal amino group and all lysine residues in -Lg, with the exception of Lys101, may be lactosylated, depending on the duration and severity of heat treatment as well as on the water activity (Morgan et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

“…The electrophoretic mobility, , is a function of the electric force, F "qE, and of the frictional force, F "6 rv, where q is the net charge, E is the electrical field strength, is the viscosity of the buffer, r is the radius and v the migration velocity. At constant migration velocity these forces are balanced, which means that the electrophoretic mobility is a function of the charge/radius ratio: "q/6 r. The attachment of lactosyl groups with the formation of a stable ketoamine may lead to slight changes in the charge of the protein (Morgan et al, 1998;Nacka et al, 1998). Furthermore, the size and conformation of the protein may be slightly changed, which may increase the frictional force and affect the migration of the condensation product.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Lactosylated β-Lactoglobulin by Capillary Electrophoresis

Otte

Larsen

Bouhallab

1998

International Dairy Journal

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Variously lactosylated species of -lactoglobulin AB were analysed by capillary electrophoresis at low pH and high pH with and without buffer additives. By simple capillary zone electrophoresis at either low or high pH the lactosylated forms had longer migration times than the native -lactoglobulin, most likely due to their larger molecular size and lower pI. By micellar electrokinetic chromatography using SDS as detergent the lactosylated forms of -lactoglobulin had shorter migration times than the native species, due to less interaction with the micelles. The methods used were also able to distinguish between more or less lactosylated forms of -lactoglobulin. By all methods used, partial separation of at least five forms of -lactoglobulin were obtained. However, baseline separation of -lactoglobulin with varying number of lactose units attached was not obtained, probably due to the presence of both variants of -lactoglobulin with various numbers of lactosyl groups at different sites.

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Lactolation of β-Lactoglobulin Monitored by Electrospray Ionisation Mass Spectrometry

Cited by 83 publications

References 0 publications

Mass spectrometric characterization of glycated β-lactoglobulin peptides derived from galacto-oligosaccharides surviving the in vitro gastrointestinal digestion

Mass spectrometric characterization of glycated β-lactoglobulin peptides derived from galacto-oligosaccharides surviving the in vitro gastrointestinal digestion

Lactose crystallisation and early Maillard reaction in skim milk powder and whey protein concentrates

Analysis of Lactosylated β-Lactoglobulin by Capillary Electrophoresis

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