Sequence characterization and glycosylation sites identification of donkey milk lactoferrin by multiple enzyme digestions and mass spectrometry

ANALYSIS OF CARBOHYDRATES AND GLYCOCONJUGATES BY MATRIX-ASSISTED LASER DESORPTION/IONIZATION MASS SPECTROMETRY: AN UPDATE FOR 2015-2016

This review is the ninth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2016. Also included are papers that describe methods appropriate to analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly-saccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis. The reported work shows increasing use of combined new techniques such as ion mobility and the enormous impact that MALDI imaging is having. MALDI, although invented over 30 years ago is still an ideal technique for carbohydrate analysis and advancements in the technique and range of applications show no sign of deminishing. © 2020 Wiley Periodicals, Inc.

Sequence and N-glycan diversity analysis of immunoglobulin G from buffalo milk using RP-UHPLC MS/MS

Immunoglobulin G is the abundant antibody present in the colostrum and milk of major dairy animals. In the present study, buffalo milk IgG was characterized for its amino acid sequence and glycan diversity using reverse phase liquid chromatography coupled to ESI-Q-TOF MS in tandem mode. Amino acid sequence analysis of heavy chain constant region revealed the presence of two IgG subtypes namely IgG1 and IgG3, with IgG1 being the abundant. The complete light chain constant region sequence was also determined. N-glycan sequence analysis at a highly conserved site Asn-Ser-Thr revealed the presence of mainly biantennary complex type with core fucosylation (34%), bisecting GlcNAc (19%) and sialylation with both Neu5Ac and Neu5Gc (14%). The observed glycan diversity in buffalo milk IgG is in part comparable with bovine colostrum as well as human, bovine, goat serum counterparts.

A MALDI-TOF MS Approach for Mammalian, Human, and Formula Milks' Profiling

Human milk composition is dynamic, and substitute formulae are intended to mimic its protein content. The purpose of this study was to investigate the potentiality of matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS), followed by multivariate data analyses as a tool to analyze the peptide profiles of mammalian, human, and formula milks. Breast milk samples from women at different lactation stages (2 (n = 5), 30 (n = 6), 60 (n = 5), and 90 (n = 4) days postpartum), and milk from donkeys (n = 4), cows (n = 4), buffaloes (n = 7), goats (n = 4), ewes (n = 5), and camels (n = 2) were collected. Different brands (n = 4) of infant formulae were also analyzed. Protein content (<30 kDa) was analyzed by MS, and data were exported for statistical elaborations. The mass spectra for each milk closely clustered together, whereas different milk samples resulted in well-separated mass spectra. Human samples formed a cluster in which colostrum constituted a well-defined subcluster. None of the milk formulae correlated with animal or human milk, although they were specifically characterized and correlated well with each other. These findings propose MALDI-TOF MS milk profiling as an analytical tool to discriminate, in a blinded way, different milk types. As each formula has a distinct specificity, shifting a baby from one to another formula implies a specific proteomic exposure. These profiles may assist in milk proteomics for easiness of use and minimization of costs, suggesting that the MALDI-TOF MS pipelines may be useful for not only milk adulteration assessments but also for the characterization of banked milk specimens in pediatric clinical settings.

Proteomic Analyses on an Ancient Egyptian Cheese and Biomolecular Evidence of Brucellosis

The material analyzed in this study is probably the most ancient archeological solid residue of cheese ever found to date. The sample was collected during the Saqqara Cairo University excavations in the tomb of Ptahmes dated to XIX dynasty ( El-Aguizy, O. Bulletin de l'Institut Française d'Archéologie Orientale (BIFAO) 2010 , 110 , 13 - 34 (ref (1) ); Staring, N. Bulletin de Institut Français d'Archéologie Orientale (BIFAO) 2015 , 114 , 455 - 518 (ref (2) )). Our biomolecular proteomic characterization of this archeological sample shows that the constituting material was a dairy product obtained by mixing sheep/goat and cow milk. The interactions for thousands of years with the strong alkaline environment of the incorporating soil rich in sodium carbonate and the desertic conditions did not prevent the identification of specific peptide markers which showed high stability under these stressing conditions. Moreover, the presence of Brucella melitensis has been attested by specific peptide providing a reasonable direct biomolecular evidence of the presence of this infection in the Ramesside period for which only indirect paleopathological evidence has been so far provided ( Pappas, G.; Papadimitriou P. Int. J. Antimicrob. Agents 2007 , 30 , 29 - 31 (ref (3) ); Bourke, J. B. Medical History 1971 , 15 ( 4 ), 363 - 375 (ref (4) )). Finally, it is worth noting that, although proteomic approaches are successfully and regularly used to characterize modern biological samples ( D'Ambrosio, C.; Arena, S.; Salzano, A. M.; Renzone, G.; Ledda, L.; and Scaloni, A. Proteomics 2008 8 , 3657 - 3666 (ref (5) ), their application in ancient materials is still at an early stage of progress, only few results being reported about ancient food samples ( Yang, Y.; Shevchenko, A.; Knaust, A.; Abuduresule, I.; Li, W.; Hu, X.; Wang, C.; Shevchenko, A. J. Archaeol. Sci. 2014 , 45 , 178 - 186 (ref (6) ). In the absence of previous relevant evidence of cheese production and/or use, this study, undoubtedly has a clear added value in different fields of knowledge ranging from archaeometry, anthropology, archeology, medicine history to the forensic sciences.

Proteins and bioactive peptides from donkey milk: The molecular basis for its reduced allergenic properties

The legendary therapeutics properties of donkey milk have recently been supported by many clinical trials who have clearly demonstrated that, even if with adequate lipid integration, it may represent a valid natural substitute of cow milk for feeding allergic children. During the last decade many investigations by MS-based methods have been performed in order to obtain a better knowledge of donkey milk proteins. The knowledge about the primary structure of donkey milk proteins now may provide the basis for a more accurate comprehension of its potential benefits for human nutrition. In this aspect, experimental data today available clearly demonstrate that donkey milk proteins (especially casein components) are more closely related with the human homologues rather than cow counterparts. Moreover, the low allergenic properties of donkey milk with respect to cow one seem to be related to the low total protein content, the low ratio of caseins to whey fraction, and finally to the presence in almost all bovine IgE-binding linear epitopes of multiple amino acid differences with respect to the corresponding regions of donkey milk counterparts.

Recent advances in mass spectrometric analysis of glycoproteins

Glycosylation is one of the most common posttranslational modifications of proteins that plays essential roles in various biological processes, including protein folding, host-pathogen interaction, immune response, and inflammation and aberrant protein glycosylation is a well-known event in various disease states including cancer. As a result, it is critical to develop rapid and sensitive methods for the analysis of abnormal glycoproteins associated with diseases. Mass spectrometry (MS) in conjunction with different separation methods, such as capillary electrophoresis (CE), ion mobility (IM), and high performance liquid chromatography (HPLC) has become a popular tool for glycoprotein analysis, providing highly informative fragments for structural identification of glycoproteins. This review provides an overview of the developments and accomplishments in the field of glycomics and glycoproteomics reported between 2014 and 2016.