This research was generously funded by the NIH NCI IMAT Program Grant R33 (CA147988-02), the NIH NIGMS Graduate Training in Molecular Biotechnology at NC State Grant (T32GM008776), the US Dept. of Education GAANN Fellowship Program in Molecular Biotechnology at NC State Grant (P200A140020), the W.M. Keck Foundation, and North Carolina State University. Hen plasma was obtained with the assistance of Dr. James N. Petitte and Rebecca Wysocky in the NC State University Dept. of Poultry Science.

<ol>
	<li>Wisniewski, J. R., Zougman, A., Nagaraj, N., Mann, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Universal+sample+preparation+method+for+proteome+analysis.">Universal sample preparation method for proteome analysis.</a> Nat. Meth. 6, 359-362 (2009).</li><li>Preston, R. J. S., Rawley, O., Gleeson, E. M., O'Donnell, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Elucidating+the+role+of+carbohydrate+determinants+in+regulating+hemostasis:+insights+and+opportunities.">Elucidating the role of carbohydrate determinants in regulating hemostasis: insights and opportunities.</a> Blood. 121, 3801-3810 (2013).</li><li>Hasnain, S. Z., Gallagher, A. L., Grencis, R. K., Thornton, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+role+for+mucins+in+immunity:+Insights+from+gastrointestinal+nematode+infection.">A new role for mucins in immunity: Insights from gastrointestinal nematode infection.</a> Int. J. Biochem. Cell Biol. 45, 364-374 (2013).</li><li>Roseman, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reflections+on+glycobiology.">Reflections on glycobiology.</a> J. Biol. Chem. 276, 41527-41542 (2001).</li><li>Laine, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+calculation+of+all+possible+oligosaccharide+isomers+both+branched+and+linear+yields+1.05+x+10(12)+structures+for+a+reducing+hexasaccharide:+The+isomer+barrier+to+development+of+single-method+saccharide+sequencing+or+synthesis+systems.">A calculation of all possible oligosaccharide isomers both branched and linear yields 1.05 x 10(12) structures for a reducing hexasaccharide: The isomer barrier to development of single-method saccharide sequencing or synthesis systems.</a> Glycobiology. 4, 759-767 (1994).</li><li>Zaia, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mass+spectrometry+and+glycomics.">Mass spectrometry and glycomics.</a> Omics. 14, 401-418 (2010).</li><li>Hirabayashi, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lectin-based+structural+glycomics:+Glycoproteomics+and+glycan+profiling.">Lectin-based structural glycomics: Glycoproteomics and glycan profiling.</a> Glycoconjugate J. 21, 35-40 (2004).</li><li>Nilsson, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enrichment+of+glycopeptides+for+glycan+structure+and+attachment+site+identification.">Enrichment of glycopeptides for glycan structure and attachment site identification.</a> Nat. Methods. 6, 809-811 (2009).</li><li>Redmond, J. W., Packer, N. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+solid-phase+extraction+with+graphitised+carbon+for+the+fractionation+and+purification+of+sugars.">The use of solid-phase extraction with graphitised carbon for the fractionation and purification of sugars.</a> Carbohyd. Res. 319, 74-79 (1999).</li><li>Ruhaak, L. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrophilic+interaction+chromatography-based+high-throughput+sample+preparation+method+for+N-glycan+analysis+from+total+human+plasma+glycoproteins.">Hydrophilic interaction chromatography-based high-throughput sample preparation method for N-glycan analysis from total human plasma glycoproteins.</a> Anal. Chem. 80, 6119-6126 (2008).</li><li>Kim, Y. -. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+and+high-throughput+analysis+of+N-glycans+from+ovarian+cancer+serum+using+a+96-well+plate+platform.">Rapid and high-throughput analysis of N-glycans from ovarian cancer serum using a 96-well plate platform.</a> Anal. Biochem. 391, 151-153 (2009).</li><li>Zielinska, D. F., Gnad, F., Wi&#347;niewski, J. R., Mann, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Precision+mapping+of+an+in+vivo+N-glycoproteome+reveals+rigid+topological+and+sequence+constraints.">Precision mapping of an in vivo N-glycoproteome reveals rigid topological and sequence constraints.</a> Cell. 141, 897-907 (2010).</li><li>Abdul Rahman, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Filter-aided+N-glycan+separation+(FANGS):+a+convenient+sample+preparation+method+for+mass+spectrometric+N-glycan+profiling.">Filter-aided N-glycan separation (FANGS): a convenient sample preparation method for mass spectrometric N-glycan profiling.</a> J. Proteome Res. 13, 1167-1176 (2014).</li><li>Walker, S. H., Carlisle, B. C., Muddiman, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Systematic+comparison+of+reverse+phase+and+hydrophilic+interaction+liquid+chromatography+platforms+for+the+analysis+of+N-linked+glycans.">Systematic comparison of reverse phase and hydrophilic interaction liquid chromatography platforms for the analysis of N-linked glycans.</a> Anal. Chem. 84, 8198-8206 (2012).</li><li>Walker, S. H., Taylor, A. D., Muddiman, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Individuality+normalization+when+labeling+with+isotopic+glycan+hydrazide+tags+(INLIGHT):+A+novel+glycan-relative+quantification+strategy.">Individuality normalization when labeling with isotopic glycan hydrazide tags (INLIGHT): A novel glycan-relative quantification strategy.</a> J. Am. Soc. Mass Spectr. 24, 1376-1384 (2013).</li><li>Walker, S. H., Lilley, L. M., Enamorado, M. F., Comins, D. L., Muddiman, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrophobic+derivatization+of+N-linked+glycans+for+increased+ion+abundance+in+electrospray+ionization+mass+spectrometry.">Hydrophobic derivatization of N-linked glycans for increased ion abundance in electrospray ionization mass spectrometry.</a> J. Am. Soc. Mass. Spectr. 22, 1309-1317 (2011).</li><li>Baldwin, M. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Permethylation+and+tandem+mass+spectrometry+of+oligosaccharides+having+free+hexosamine:+Analysis+of+the+glycoinositol+phospholipid+anchor+glycan+from+the+scrapie+prion+protein.">Permethylation and tandem mass spectrometry of oligosaccharides having free hexosamine: Analysis of the glycoinositol phospholipid anchor glycan from the scrapie prion protein.</a> Anal. Biochem. 191, 174-182 (1990).</li><li>Harvey, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Derivatization+of+carbohydrates+for+analysis+by+chromatography;+electrophoresis+and+mass+spectrometry.">Derivatization of carbohydrates for analysis by chromatography; electrophoresis and mass spectrometry.</a> J. Chromatogr. B. 879, 1196-1225 (2011).</li><li>Bradford, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+rapid+and+sensitive+method+for+the+quantitation+of+microgram+quantities+of+protein+utilizing+the+principle+of+protein-dye+binding.">A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding.</a> Anal. Biochem. 72, 248-254 (1976).</li><li>Smith, P. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+protein+using+bicinchoninic+acid.">Measurement of protein using bicinchoninic acid.</a> Anal. Biochem. 150, 76-85 (1985).</li><li>Hecht, E. S., McCord, J. P., Muddiman, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Definitive+screening+design+optimization+of+mass+spectrometry+parameters+for+sensitive+comparison+of+filter+and+solid+phase+extraction+purified,+inlight+plasma+N-glycans.">Definitive screening design optimization of mass spectrometry parameters for sensitive comparison of filter and solid phase extraction purified, inlight plasma N-glycans.</a> Anal. Chem. 87, 7305-7312 (2015).</li><li>Nepomuceno, A. I., Gibson, R. J., Randall, S. M., Muddiman, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accurate+identification+of+deamidated+peptides+in+global+proteomics+using+a+quadrupole+orbitrap+mass+spectrometer.">Accurate identification of deamidated peptides in global proteomics using a quadrupole orbitrap mass spectrometer.</a> J. Proteome Res. 13, 777-785 (2013).</li><li>Yen, T. -. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overcoming+challenges+and+opening+new+opportunities+in+glycoproteomics.">Overcoming challenges and opening new opportunities in glycoproteomics.</a> Biomolecules. 3, 270-286 (2013).</li><li>Meiring, H. D., van der Heeft, E., ten Hove, G. J., de Jong, A. P. J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoscale+LC-MS(n):+technical+design+and+applications+to+peptide+and+protein.">Nanoscale LC-MS(n): technical design and applications to peptide and protein.</a> J. Sep. Sci. 25, 557-568 (2002).</li><li>Apweiler, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=UniProt:+the+Universal+Protein+knowledgebase.">UniProt: the Universal Protein knowledgebase.</a> Nucleic Acids Res. 32, 115-119 (2004).</li><li>Perkins, D. N., Pappin, D. J. C., Creasy, D. M., Cottrell, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Probability-based+protein+identification+by+searching+sequence+databases+using+mass+spectrometry+data.">Probability-based protein identification by searching sequence databases using mass spectrometry data.</a> Electrophoresis. 20, 3551-3567 (1999).</li><li>Eng, J. K., McCormack, A. L., Yates, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+approach+to+correlate+tandem+mass+spectral+data+of+peptides+with+amino+acid+sequences+in+a+protein+database.">An approach to correlate tandem mass spectral data of peptides with amino acid sequences in a protein database.</a> J. Am. Soc. Mass. Spectrom. 5, 976-989 (1994).</li><li>Gonzalez-Galarza, F. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+critical+appraisal+of+techniques,+software+packages,+and+standards+for+quantitative+proteomic+analysis.">A critical appraisal of techniques, software packages, and standards for quantitative proteomic analysis.</a> Omics. 16, 431-442 (2012).</li><li>Spivak, M., Weston, J., Bottou, L., K&#228;ll, L., Noble, W. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improvements+to+the+Percolator+Algorithm+for+Peptide+Identification+from+Shotgun+Proteomics+Data+Sets.">Improvements to the Percolator Algorithm for Peptide Identification from Shotgun Proteomics Data Sets.</a> J Proteome Res. 8, 3737-3745 (2009).</li><li>Collier, T. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+stable-isotope+labeling+with+amino+acids+in+cell+culture+and+spectral+counting+for+relative+quantification+of+protein+expression.">Comparison of stable-isotope labeling with amino acids in cell culture and spectral counting for relative quantification of protein expression.</a> Rapid Commun Mass Sp. 25, 2524-2532 (2011).</li><li>Kronewitter, S. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+development+of+retrosynthetic+glycan+libraries+to+profile+and+classify+the+human+serum+N-linked+glycome.">The development of retrosynthetic glycan libraries to profile and classify the human serum N-linked glycome.</a> Proteomics. 9, 2986-2994 (2009).</li><li>Sheeley, D. M., Reinhold, V. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+characterization+of+carbohydrate+sequence,+linkage,+and+branching+in+a+quadrupole+ion+trap+mass+spectrometer:+Neutral+oligosaccharides+and+N-linked+glycans.">Structural characterization of carbohydrate sequence, linkage, and branching in a quadrupole ion trap mass spectrometer: Neutral oligosaccharides and N-linked glycans.</a> Anal. Chem. 70, 3053-3059 (1998).</li></ol>

We have a collaborative relationship with Cambridge Isotope Laboratories (CIL) to disseminate the P2GPN reagent and technology to the broader scientific community in the form of a product (GTK-1000). However, we do not receive any revenue based on the sale of this product.

High-throughput quantitative methods are needed to facilitate routine glycan analysis. For the last thirty years, glycomics analysis has been limited to a subset of research groups, despite its importance in disease, clinical applications, and pharmaceuticals. The FANGS-P2GPN purification and tagging method for glycomics and proteomics performs the same analysis on a single aliquot of sample, reducing the cost of supplies and the amount of material needed (particularly important in human and mouse studies). Furthermore, efforts to minimize variability in preparations are critically important, as every additional step contributes to error, potentially masking important but low-abundant changes in case-control studies. Coupling of FANGS to hydrophobic hydrazide tagging allows protein and glycan samples to be run on the same RPLC column, enhances glycan ionization, provides for relative quantification, and can be quantitatively applied to plasma.
For N-glycan analysis, it is critical to use the suggested level of PNGase F to achieve full de-glycosylation. Though glycans are solvent exposed, denaturation of proteins and excess enzyme help ensure efficient and complete cleavage. For accurate quantitation of the glycans, it is necessary to ensure that they are completely dried after derivatization to quench the reaction and prevent cross-reactions when mixing the NAT and SIL species. Finally, when extending the workflow to glycosite analysis, timing of the steps is critical to minimize non-specific deamidation. The modified protocols provided for combined glycomics and proteomics analysis work consistently when performed accordingly.
The workflow achieves accurate relative quantitation of N-glycans from plasma compared to the gold-standard, SPE method. There is no apparent bias in the types of glycans extracted in terms of molecular weight, hydrophilicity, and compositional structure. Though we have not explored the qualitative analysis of O-linked glycans, we expect that FANGS could accommodate the addition of a &#946;-elimination step post-PNGase F digestion of N-linked glycans. However, procedures would require significant modification for reagent cleanup prior to mass spectrometry, and peptide analysis will be significantly impacted. For proteomics, the same depth of proteome coverage is achieved compared to traditional FASP methods. Importantly, methods achieve a minimal false discovery rate for N-glycan deamidation. While the method is compatible with 18O labeling of Asn during the PNGase digestion step22,23, the low glycosylation site false discovery rate suggests that it may not be necessary, further reducing costs and complexity.
The proteome is not enriched for glycoproteins in this method, which has both advantages and disadvantages. Certain low abundant glycoproteins may not be detected in the analysis. However, the occupancy of glycosylated sites per protein, can be compared between biological samples. Additionally, the error and bias introduced from lectin affinity purification or chemical enrichment is eliminated. In conclusion, coupling of FANGS to the individuality normalization when labeling with glycan hydrazide tags strategy results in a simplified, quantitative, high-throughput method for the tandem analysis of the glycome and proteome with great potential for application in clinical case-control studies.

In the field of proteomics, filter aided sample preparation (FASP) has been widely adopted for its ability to minimize the amount of starting material, decrease sample preparation artifacts, and maximize sample throughput1. However, such a method has yet to emerge and gain traction for the field of glycomics. Development of high-throughput, quantitative workflows are needed because of the integral role of glycosylation in biological defense and its modulation by cancer or diseases2,3. In mammals, N-glycans are composed of repeating saccharide units (hexoses (Hex), hexosamines (HexNac), sialic acids (NeuAc), and fucoses (Fuc)), which decorate a core structure (Hex3HexNac2)4 covalently bound to asparagine. Though the glycospace is considerably large when isomers are counted (&#62;1012), it is quite small on a composition basis and molecular weights typically range from 1,000-8,000 Da5. The compositional homogeneity of the class and the hydrophilicity of glycans pose unique challenges to purification, separation, and mass spectrometry (MS) workflows6.
Traditionally, N-glycans are digested from proteins or peptides by peptide-N-glycosidase F (PNGase F) and then enriched by lectin affinity chromatography7, captured by hydrazide beads8, or purified via solid phase extraction (SPE)9,10. While these methods are all highly effective, they introduce extra steps for desalting and limit the number of samples simultaneously processed. Over the last decade, a number of high-throughput platforms for glycomics have been proposed. Kim et al. published a semi-automated method using a vacuum-operated, SPE 96-well plate11. Alternatively, an affinity-filter method (N-glyco-FASP) was developed by the Mann group, which required the initial derivatization of the filter with a composite of lectins12. Lastly, the Thomas-Oates group proposed a semi-quantitative method, the Filter Aided N-Glycan Separation (FANGS), which exploited the narrow composition size of the glycospace13. Relying on molecular weight cut-off filters, small contaminants were first washed to waste and then the N-glycans were digested and eluted. Deglycosylated proteins remain on the filter in this protocol and can be subjected to in-line FASP.
Identification and quantification of glycans by electrospray ionization (ESI) MS requires off-line separations for (partial) resolution of isomers and derivatization for detection of low-abundant species. Labeling in the individuality when normalizing with glycan hydrazide tags strategy confers compatibility with reverse-phase liquid chromatography (RPLC)14,15. The 4-phenethyl-benzohydrazide (P2PGN) hydrophobic tag mediates the hydrophilicity of the glycans, enhancing ionization by, on average, four-fold16. Though other techniques, such as permethylation17 or amine-reactive tagging chemistries18, offer similar advantages, in the hydrazide reaction, glycans are reacted 1:1 stoichiometrically in facile conditions. Relative quantification is achieved by tandem analysis of samples derivatized with native (NAT) or 13C6 stabile isotope labels (SIL).
The following method evolves FANGS for plasma applications and couples it to the P2GPN hydrophobic tag for accurate relative quantification. Furthermore, it was designed to perform shot-gun proteomics, deamidation profiling, and quantitative glycomics on a single aliquot of sample, without compromising the integrity of the analyses.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr >
			<td >Acetic Acid (50%):&#160;</td>
			<td >Sigma Aldrich&#160;</td>
			<td >45754</td>
			<td ></td>
		</tr>
		<tr >
			<td >Acetonitrile, HPLC grade</td>
			<td >Burdick &#38; Jackson&#160;</td>
			<td >AH015-4</td>
			<td ></td>
		</tr>
		<tr >
			<td >Ammonium Bicarbonate</td>
			<td >Sigma Aldrich&#160;</td>
			<td >A6141</td>
			<td ></td>
		</tr>
		<tr >
			<td >Bradford Reagent</td>
			<td >Sigma Aldrich&#160;</td>
			<td >B6916</td>
			<td>Alternative: Bicinchoninic acid kit (Sigma Aldrich BCA1)</td>
		</tr>
		<tr >
			<td >Calcium chloride</td>
			<td >Sigma Aldrich&#160;</td>
			<td >C1016</td>
			<td></td>
		</tr>
		<tr >
			<td >Centrifuge</td>
			<td >Eppendorf</td>
			<td >5804 R</td>
			<td >Alternate centrifuges that reach 14,000 x g are suitable</td>
		</tr>
		<tr >
			<td >DL-Dithiothreitol, 1M in solution</td>
			<td >Sigma Aldrich&#160;</td>
			<td >646563</td>
			<td ></td>
		</tr>
		<tr >
			<td >Easy-nLC 1000</td>
			<td >Thermo Scientific</td>
			<td >LC120</td>
			<td >Alternate nano or ultra high pressure LCs will produce similar data, such as: 1. Dionex UltiMate&#210; 3000 LC (Thermo Scientific) 2. Acquity UPLC (Waters)</td>
		</tr>
		<tr >
			<td >Floating Tube Rack</td>
			<td >TedPella</td>
			<td >20831-20</td>
			<td></td>
		</tr>
		<tr >
			<td >Fetuin</td>
			<td >New England Biolabs&#160;</td>
			<td >P6042S</td>
			<td ></td>
		</tr>
		<tr >
			<td >Fisher Scientific Isotemp Standard Lab Ovens</td>
			<td >Fisher Scientific</td>
			<td >11-690-625F</td>
			<td >Alternate incubators that reach 56 &#176;C are suitable</td>
		</tr>
		<tr >
			<td >Formic Acid</td>
			<td >Sigma Aldrich&#160;</td>
			<td >56302</td>
			<td ></td>
		</tr>
		<tr >
			<td >GE Microwave Oven</td>
			<td >General Electric</td>
			<td >57B5 E82904</td>
			<td >Any microwave with adjustable power settings is suitable</td>
		</tr>
		<tr >
			<td >INLIGHT Glycan Tagging Kit&#160;</td>
			<td >Cambridge Isotope Laboratories</td>
			<td >GTK-1000</td>
			<td >The INLIGHT kit provides NAT and SIL versions of the P2GPN reagent.</td>
		</tr>
		<tr >
			<td >Iodoacetamide</td>
			<td >Sigma Aldrich&#160;</td>
			<td >A3221</td>
			<td></td>
		</tr>
		<tr >
			<td >Kinetix 2.6 mM, 100 &#197;, C18 bulk stationary phase</td>
			<td >Phenomenex&#160;</td>
			<td>Bulk Media</td>
			<td >Alternative: Any C18 stationary phase &#163; 5 mM&#160;</td>
		</tr>
		<tr >
			<td >Mascot Daemon Software and Server</td>
			<td >Matrix Science</td>
			<td ></td>
			<td >Alternative: Proteome Discoverer Software (Thermo Scientific)</td>
		</tr>
		<tr >
			<td >Methanol, HPLC grade</td>
			<td >Burdick &#38; Jackson&#160;</td>
			<td >AH230-4</td>
			<td ></td>
		</tr>
		<tr >
			<td >PicoFrit Self-Pack Column: 360 um, OD 75um ID, 15 um tip, non-coated, 5 per box, 50 cm</td>
			<td >New Objective</td>
			<td >1 5 PF360-75-15-N-5</td>
			<td></td>
		</tr>
		<tr >
			<td >PNGase F (glycerol-free), 75,000 units/ml</td>
			<td >New England BioLabs&#160;</td>
			<td >P0705L</td>
			<td ></td>
		</tr>
		<tr >
			<td >Q Exactive HF Hybrid Quadrupole-Orbitrap Mass Spectrometer</td>
			<td >Thermo Scientific</td>
			<td ></td>
			<td >Alternate high mass accuracy (&#163; 5 ppm) mass spectrometers will provide similar data</td>
		</tr>
		<tr >
			<td >RNase B</td>
			<td >New England Biolabs&#160;</td>
			<td >P7817S</td>
			<td ></td>
		</tr>
		<tr >
			<td >Trypsin from Porcine Pancreas</td>
			<td >Sigma Aldrich&#160;</td>
			<td >T6567-5X</td>
			<td></td>
		</tr>
		<tr >
			<td >Urea</td>
			<td >Sigma Aldrich&#160;</td>
			<td >51456</td>
			<td></td>
		</tr>
		<tr >
			<td >Vacuum ConcentratorSavant SPD131DDA SpeedVac Concentrator</td>
			<td >Thermo Scientific</td>
			<td >SPD131DDA</td>
			<td >Alternate vacuum concentrators are suitable</td>
		</tr>
		<tr >
			<td >Vivacon 500 30 kDa Filters&#160;</td>
			<td >Sartorius Stedim Biotech</td>
			<td >VN01H22</td>
			<td >Alternative: Amicon Ultra 0.5 Centrifugal Filter Units with Ultracel-10 kDa Membrane (Millipore UFC501096)</td>
		</tr>
		<tr >
			<td >Water, HPLC grade</td>
			<td >Burdick &#38; Jackson&#160;</td>
			<td >AH365-4</td>
			<td ></td>
		</tr>
		<tr >
			<td >Water, 18O</td>
			<td >Cambridge Isotope Laboratories</td>
			<td >OLM-240-97-1</td>
			<td >The addition of 18O in the PNGase F digest step is optional and may not be necessary for deamidation studies completed with 95% confidence</td>
		</tr>
		<tr >
			<td >Xcalibur 2.0</td>
			<td >Thermo Scientific</td>
			<td>XCALIBUR20</td>
			<td></td>
		</tr>
		<tr >
			<td >Zwittergent Test Kit</td>
			<td >Merck Millipore</td>
			<td >693030</td>
			<td></td>
		</tr>
	</tbody>
</table>

a quantitative glycomics and proteomics combined purification strategy

There is a growing desire in the biological and clinical sciences to integrate and correlate multiple classes of biomolecules to unravel biology, define pathways, improve treatment, understand disease, and aid biomarker discovery. N-linked glycosylation is one of the most important and robust post-translational modifications on proteins and regulates critical cell functions such as signaling, adhesion, and enzymatic function. Analytical techniques to purify and analyze N-glycans have remained relatively static over the last decade. While accurate and effective, they commonly require significant expertise and resources. Though some high-throughput purification schemes have been developed, they have yet to find widespread adoption and often rely on the enrichment of glycopeptides. One promising method, developed by Thomas-Oates et al., filter aided N-glycan separation (FANGS), was qualitatively demonstrated on tissues. Herein, we adapted FANGS to plasma and coupled it to the individuality normalization when labeling with glycan hydrazide tags strategy in order to achieve accurate relative quantification by liquid chromatography mass spectrometry and enhanced electrospray ionization. Furthermore, we designed new functionality to the protocol by achieving tandem, shotgun proteomics and glycosylation site analysis on hen plasma. We showed that N-glycans purified on filter and derivatized by hydrophobic hydrazide tags were comparable in terms of abundance and class to those by solid phase extraction (SPE); the latter is considered a gold standard in the field. Importantly, the variability in the two protocols was not statistically different. Proteomic data that was collected in-line with glycomic data had the same depth compared to a standard trypsin digest. Peptide deamidation is minimized in the protocol, limiting non-specific deamidation detected at glycosylation motifs. This allowed for direct glycosylation site analysis, though the protocol can accommodate 18O site labeling as well. Overall, we demonstrated a new in-line high-throughput, unbiased, filter based protocol for quantitative glycomics and proteomics analysis.

<img alt="Figure 1" src="/files/ftp_upload/53735/53735fig1.jpg" /> 
Figure 1: The scheme of the FANGS-P2GPN hydrophobic tagging coupled method (Method A) for combined proteomics and glycomics analysis is given. Steps that differ between glycomics-only processing and tandem glycomics and proteomics analysis, with glycosylation site identification, are highlighted. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53735/53735fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
The in-line proteomics and glycomics, filter-based P2GPN hydrophobic tagging method (Method A) was validated for identification, quantitation, and molecular weight bias using pooled hen plasma samples (Figure 1). For solely glycomics experiments, inter-comparisons in the abundances of N-glycans extracted by Method A to carbograph SPE (gold-standard, Method B) were made (Figure 2). There were no significant differences in the abundances of glycans between the two methods. The intra-variability was also assessed by quantifying the SIL: NAT ratio of glycans extracted by the same method. The log2-distributions of both methods were Gaussian, centered on zero, and not significantly different (Figure 3A-B). The molecular weight ranges between the two protocols completely overlapped, suggesting that the filter did not discriminate N-glycans based on molecular weight range and hydrophilicity (Figure 4).
<img alt="Figure 2" src="/files/ftp_upload/53735/53735fig2.jpg" /> 
Figure 2: An equimolar mixture of NAT and SIL N-glycans extracted by Method A or Method B was prepared from 2.5 &#956;l of hen plasma (N = 4). Samples were analyzed by UPLC-MS according to the recommended parameters suggested in section 6. The abundances for each glycan, in each NAT/SIL channel, were calculated by integrating the area under the extracted ion chromatogram (MMA = 3 ppm), correcting for the molecular weight overlap, and adjusting by the TGNF. These ratios are shown with their standard errors. The abundances of Method B: Method A N-glycans were not significantly different (p &#62;0.05). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53735/53735fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" src="/files/ftp_upload/53735/53735fig3.jpg" /> 
Figure 3: The intra-variability in the (A) Method A (N = 133) or (B) Method B (N = 123) strategies was compared. NAT and SIL equimolar mixtures of N-glycans, from the same extraction scheme, were analyzed over three technical replicates. The log2-distributions were centered on zero and were not significantly different between the two workflows. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53735/53735fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" src="/files/ftp_upload/53735/53735fig4.jpg" /> 
Figure 4: The molecular weight ranges of glycans from each strategy were compared. The two workflows yielded glycans spanning the same molecular weight range. N-glycans detected in one protocol versus the other fell just above the limit of detection (1 &#215; 105 abundance) and do not reflect systematic bias. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53735/53735fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
Retention of the deglycosylated proteins by the molecular weight filter enabled in-line proteome wide analysis and glycosylation site identification. Multiple protocols for the combined purification of glycans and proteins were compared to a traditional FASP preparation without deglycosylation (Table 5). Our typical 18 hr filter based PNGase F digestion, followed by FASP trypsin digest (Std protocol) resulted in significant levels of non-specific deamidation, which can interfere with the identification of glycosites. Therefore, a method utilizing a shorter incubation time at elevated temperature (50 &#176;C) and a PNGase F spike-in step (SPI protocol) was explored as an alternative, along with a microwave digestion protocol (MD protocol), to minimize non-specific deamidation. The glycans observed in the new digestion methods were not significantly different in compositions or abundances from the standard 18 hr, 37 &#176;C filter PNGase F digest (Figure 5). Combined with a short trypsin incubation, non-specific deamidation was significantly reduced, with a false positive rate for glycosites &#60;5% (Table 5).
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td colspan="2"></td>
			<td colspan="4">Proteins</td>
			<td></td>
			<td colspan="4">Peptides</td>
			<td></td>
			<td colspan="4">Deamidated Peptides</td>
			<td></td>
			<td colspan="4">Glycosites</td>
			<td></td>
			<td colspan="4">Glycoproteins</td>
		</tr>
		<tr>
			<td colspan="2"></td>
			<td colspan="2">+</td>
			<td colspan="2">-</td>
			<td></td>
			<td colspan="2">+</td>
			<td colspan="2">-</td>
			<td></td>
			<td colspan="2">+</td>
			<td colspan="2">-</td>
			<td></td>
			<td colspan="2">+</td>
			<td colspan="2">-</td>
			<td></td>
			<td colspan="2">+</td>
			<td colspan="2">-</td>
		</tr>
		<tr>
			<td colspan="2">FASP</td>
			<td colspan="2"></td>
			<td colspan="2">249</td>
			<td></td>
			<td colspan="2"></td>
			<td colspan="2">3083</td>
			<td></td>
			<td colspan="2"></td>
			<td colspan="2">795</td>
			<td></td>
			<td colspan="2"></td>
			<td colspan="2">5</td>
			<td></td>
			<td colspan="2"></td>
			<td colspan="2">5</td>
		</tr>
		<tr>
			<td colspan="2">18hr</td>
			<td colspan="2">217</td>
			<td colspan="2">304</td>
			<td></td>
			<td colspan="2">6013</td>
			<td colspan="2">5086</td>
			<td></td>
			<td colspan="2">1029</td>
			<td colspan="2">733</td>
			<td></td>
			<td colspan="2">257</td>
			<td colspan="2">24</td>
			<td></td>
			<td colspan="2">112</td>
			<td colspan="2">18</td>
		</tr>
		<tr>
			<td colspan="2">MD</td>
			<td colspan="2">270</td>
			<td colspan="2">266</td>
			<td></td>
			<td colspan="2">5190</td>
			<td colspan="2">5125</td>
			<td></td>
			<td colspan="2">465</td>
			<td colspan="2">455</td>
			<td></td>
			<td colspan="2">254</td>
			<td colspan="2">8</td>
			<td></td>
			<td colspan="2">102</td>
			<td colspan="2">7</td>
		</tr>
		<tr>
			<td colspan="2">SPI</td>
			<td colspan="2">281</td>
			<td colspan="2">288</td>
			<td></td>
			<td colspan="2">4729</td>
			<td colspan="2">4482</td>
			<td></td>
			<td colspan="2">602</td>
			<td colspan="2">573</td>
			<td></td>
			<td colspan="2">232</td>
			<td colspan="2">10</td>
			<td></td>
			<td colspan="2">145</td>
			<td colspan="2">8</td>
		</tr>
	</tbody>
</table>
Table 5: Comparisons of proteomic data from a standard trypsin digest versus the in-line FANGS-P2GPN tagging method were made. Preparations were performed with (+) and without (-) PNGase F to determine background rates of non-specific deamidation and estimate glycosite false positive rates. Proteins were identified with 1% false discovery rate (FDR); peptides were filtered based on &#34;high&#34; peptide confidence in Proteome Discoverer 1.4 (q &#60;0.01); glycosites were identified based on unique sequences containing deamidation of the conserved glycosylation motif (N-X-S/T); and glycoproteins were defined as identified proteins containing at least one identified glycosite.
<img alt="Figure 5" src="/files/ftp_upload/53735/53735fig5.jpg" /> 
Figure 5: Shortened protocols for glycans were developed to minimize deamination in the samples and compared to the 18hr FANGS PNGase F digest. The average differences in abundances were 10% and 5% for the MD (2.2.3) and SPI (2.2.2) protocols, respectively. Of the 48 glycans identified, 90% displayed less than 1.5-fold variation.&#160; <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53735/53735fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about A Quantitative Glycomics and Proteomics Combined Purification Strategy at JoVE.com

A Quantitative Glycomics and Proteomics Combined Purification Strategy

A high-throughput protocol was developed for combined proteomics and glycomics purification and LC-MS/MS quantification in plasma. Deamidation analysis of N-linked glycosylation motifs was specific to deglycosylated sites. Accurate quantitation of N-glycans was achieved by coupling filter aided N-glycan separation to the individuality normalization when labeling with glycan hydrazide tags strategy.

There is a growing desire in the biological and clinical sciences to integrate and correlate multiple classes of biomolecules to unravel biology, define ...

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Nanyang Technological University

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14.8K Views.  North Carolina State University. A high-throughput protocol was developed for combined proteomics and glycomics purification and LC-MS/MS quantification in plasma. Deamidation analysis of N-linked glycosylation motifs was specific to deglycosylated sites. Accurate quantitation of N-glycans was achieved by coupling filter aided N-glycan separation to the individuality normalization when labeling with glycan hydrazide tags strategy.

Video: A Quantitative Glycomics and Proteomics Combined Purification Strategy

Large Scale Non-targeted Metabolomic Profiling of Serum by Ultra Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS)

Non-targeted metabolite profiling by ultra performance liquid chromatography coupled with mass spectrometry (UPLC-MS) is a powerful technique to investigate metabolism. The approach offers an unbiased and in-depth analysis that can enable the development of diagnostic tests, novel therapies, and further our understanding of disease processes. The inherent chemical diversity of the metabolome creates significant analytical challenges and there is no single experimental approach that can detect all metabolites. Additionally, the biological variation in individual metabolism and the dependence of metabolism on environmental factors necessitates large sample numbers to achieve the appropriate statistical power required for meaningful biological interpretation. To address these challenges, this tutorial outlines an analytical workflow for large scale non-targeted metabolite profiling of serum by UPLC-MS. The procedure includes guidelines for sample organization and preparation, data acquisition, quality control, and metabolite identification and will enable reliable acquisition of data for large experiments and provide a starting point for laboratories new to non-targeted metabolite profiling by UPLC-MS.

Large Scale Non-targeted Metabolomic Profiling of Serum by Ultra Performance Liquid Chromatography-Mass Spectrometry UPLC-MS

Non-targeted metabolite profiling by ultra performance liquid chromatography coupled with mass spectrometry (UPLC-MS) is a powerful technique to investigate metabolism. This article outlines a typical workflow utilized for non-targeted metabolite profiling of serum including sample organization and preparation, data acquisition, data analysis, quality control, and metabolite identification.

Non-targeted metabolite profiling by ultra performance liquid chromatography coupled with mass spectrometry (UPLC-MS) is a powerful technique to ...

Quantitative Proteomics Using Reductive Dimethylation for Stable Isotope Labeling

Stable isotope labeling of peptides by reductive dimethylation (ReDi labeling) is a method to accurately quantify protein expression differences between samples using mass spectrometry. ReDi labeling is performed using either regular (light) or deuterated (heavy) forms of formaldehyde and sodium cyanoborohydride to add two methyl groups to each free amine. Here we demonstrate a robust protocol for ReDi labeling and quantitative comparison of complex protein mixtures. Protein samples for comparison are digested into peptides, labeled to carry either light or heavy methyl tags, mixed, and co-analyzed by LC-MS/MS. Relative protein abundances are quantified by comparing the ion chromatogram peak areas of heavy and light labeled versions of the constituent peptide extracted from the full MS spectra. The method described here includes sample preparation by reversed-phase solid phase extraction, on-column ReDi labeling of peptides, peptide fractionation by basic pH reversed-phase (BPRP) chromatography, and StageTip peptide purification. We discuss advantages and limitations of ReDi labeling with respect to other methods for stable isotope incorporation. We highlight novel applications using ReDi labeling as a fast, inexpensive, and accurate method to compare protein abundances in nearly any type of sample.

Stable isotope labeling of peptides by reductive dimethylation (ReDi labeling) is a rapid, inexpensive strategy for accurate mass spectrometry-based quantitative proteomics. Here we demonstrate a robust method for preparation and analysis of protein mixtures using the ReDi approach that can be applied to nearly any sample type.

Stable isotope labeling of peptides by reductive dimethylation (ReDi labeling) is a method to accurately quantify protein expression differences between ...

Synthesis and Purification of Iodoaziridines Involving Quantitative Selection of the Optimal Stationary Phase for Chromatography

The highly diastereoselective preparation of cis-N-Ts-iodoaziridines through reaction of diiodomethyllithium with N-Ts aldimines is described. Diiodomethyllithium is prepared by the deprotonation of diiodomethane with LiHMDS, in a THF/diethyl ether mixture, at -78 &#176;C in the dark. These conditions are essential for the stability of the LiCHI2 reagent generated. The subsequent dropwise addition of N-Ts aldimines to the preformed diiodomethyllithium solution affords an amino-diiodide intermediate, which is not isolated. Rapid warming of the reaction mixture to 0 &#176;C promotes cyclization to afford iodoaziridines with exclusive cis-diastereoselectivity. The addition and cyclization stages of the reaction are mediated in one reaction flask by careful temperature control.
Due to the sensitivity of the iodoaziridines to purification, assessment of suitable methods of purification is required. A protocol to assess the stability of sensitive compounds to stationary phases for column chromatography is described. This method is suitable to apply to new iodoaziridines, or other potentially sensitive novel compounds. Consequently this method may find application in range of synthetic projects. The procedure involves firstly the assessment of the reaction yield, prior to purification, by 1H NMR spectroscopy with comparison to an internal standard. Portions of impure product mixture are then exposed to slurries of various stationary phases appropriate for chromatography, in a solvent system suitable as the eluent in flash chromatography. After stirring for 30 min to mimic chromatography, followed by filtering, the samples are analyzed by 1H NMR spectroscopy. Calculated yields for each stationary phase are then compared to that initially obtained from the crude reaction mixture. The results obtained provide a quantitative assessment of the stability of the compound to the different stationary phases; hence the optimal can be selected. The choice of basic alumina, modified to activity IV, as a suitable stationary phase has allowed isolation of certain iodoaziridines in excellent yield and purity.

A protocol for the diastereoselective one-pot preparation of cis-N-Ts-iodoaziridines is described. The generation of diiodomethyllithium, addition to N-Ts aldimines and cyclization of the amino gem-diiodide intermediate to iodoaziridines is demonstrated. Also included is a protocol to rapidly and quantitatively assess the most appropriate stationary phase for purification by chromatography.

The highly diastereoselective preparation of cis-N-Ts-iodoaziridines through reaction of diiodomethyllithium with N-Ts aldimines is described. ...

Improved In-gel Reductive &#946;-Elimination for Comprehensive O-linked and Sulfo-glycomics by Mass Spectrometry

Separation of proteins by SDS-PAGE followed by in-gel proteolytic digestion of resolved protein bands has produced high-resolution proteomic analysis of biological samples. Similar approaches, that would allow in-depth analysis of the glycans carried by glycoproteins resolved by SDS-PAGE, require special considerations in order to maximize recovery and sensitivity when using mass spectrometry (MS) as the detection method. A major hurdle to be overcome in achieving high-quality data is the removal of gel-derived contaminants that interfere with MS analysis. The sample workflow presented here is robust, efficient, and eliminates the need for in-line HPLC clean-up prior to MS. Gel pieces containing target proteins are washed in acetonitrile, water, and ethyl acetate to remove contaminants, including polymeric acrylamide fragments. O-linked glycans are released from target proteins by in-gel reductive &#946;-elimination and recovered through robust, simple clean-up procedures. An advantage of this workflow is that it improves sensitivity for detecting and characterizing sulfated glycans. These procedures produce an efficient separation of sulfated permethylated glycans from non-sulfated (sialylated and neutral) permethylated glycans by a rapid phase-partition prior to MS analysis, and thereby enhance glycomic and sulfoglycomic analyses of glycoproteins resolved by SDS-PAGE.

In order to comprehensively explore the diversity of O-linked glycans, a new procedure for in-gel reductive &#946;-elimination, combined with permethylation and a rapid phase-partition method, is applied to the analysis of O-linked glycans directly released from glycoproteins resolved by SDS-PAGE and amenable to subsequent glycomic analysis by mass spectrometry.

Separation of proteins by SDS-PAGE followed by in-gel proteolytic digestion of resolved protein bands has produced high-resolution proteomic analysis of ...

CN-GELFrEE - Clear Native Gel-eluted Liquid Fraction Entrapment Electrophoresis

Protein complexes perform an array of crucial cellular functions. Elucidating their non-covalent interactions and dynamics is paramount for understanding the role of complexes in biological systems. While the direct characterization of biomolecular assemblies has become increasingly important in recent years, native fractionation techniques that are compatible with downstream analysis techniques, including mass spectrometry, are necessary to further expand these studies. Nevertheless, the field lacks a high-throughput, wide-range, high-recovery separation method for native protein assemblies. Here, we present clear native gel-eluted liquid fraction entrapment electrophoresis (CN-GELFrEE), which is a novel separation modality for non-covalent protein assemblies. CN-GELFrEE separation performance was demonstrated by fractionating complexes extracted from mouse heart. Fractions were collected over 2 hr and displayed discrete bands ranging from ~30 to 500 kDa. A consistent pattern of increasing molecular weight bandwidths was observed, each ranging ~100 kDa. Further, subsequent reanalysis of native fractions via SDS-PAGE showed molecular-weight shifts consistent with the denaturation of protein complexes. Therefore, CN-GELFrEE was proved to offer the ability to perform high-resolution and high-recovery native separations on protein complexes from a large molecular weight range, providing fractions that are compatible with downstream protein analyses.

This protocol describes how to prepare and perform clear native gel-eluted liquid fraction entrapment electrophoresis (CN-GELFrEE), a native separation technique for non-covalent biomolecular assemblies and proteins from heterogeneous samples that is compatible with various downstream protein analysis techniques.

Protein complexes perform an array of crucial cellular functions. Elucidating their non-covalent interactions and dynamics is paramount for understanding ...

Glycan Node Analysis: A Bottom-up Approach to Glycomics

Synthesized in a non-template-driven process by enzymes called glycosyltransferases, glycans are key players in various significant intra- and extracellular events. Many pathological conditions, notably cancer, affect gene expression, which can in turn deregulate the relative abundance and activity levels of glycoside hydrolase and glycosyltransferase enzymes. Unique aberrant whole glycans resulting from deregulated glycosyltransferase(s) are often present in trace quantities within complex biofluids, making their detection difficult and sometimes stochastic. However, with proper sample preparation, one of the oldest forms of mass spectrometry (gas chromatography-mass spectrometry, GC-MS) can routinely detect the collection of branch-point and linkage-specific monosaccharides ("glycan nodes") present in complex biofluids. Complementary to traditional top-down glycomics techniques, the approach discussed herein involves the collection and condensation of each constituent glycan node in a sample into a single independent analytical signal, which provides detailed structural and quantitative information about changes to the glycome as a whole and reveals potentially deregulated glycosyltransferases. Improvements to the permethylation and subsequent liquid/liquid extraction stages provided herein enhance reproducibility and overall yield by facilitating minimal exposure of permethylated glycans to alkaline aqueous conditions. Modifications to the acetylation stage further increase the extent of reaction and overall yield. Despite their reproducibility, the overall yields of N-acetylhexosamine (HexNAc) partially permethylated alditol acetates (PMAAs) are shown to be inherently lower than their expected theoretical value relative to hexose PMAAs. Calculating the ratio of the area under the extracted ion chromatogram (XIC) for each individual hexose PMAA (or HexNAc PMAA) to the sum of such XIC areas for all hexoses (or HexNAcs) provides a new normalization method that facilitates relative quantification of individual glycan nodes in a sample. Although presently constrained in terms of its absolute limits of detection, this method expedites the analysis of clinical biofluids and shows considerable promise as a complementary approach to traditional top-down glycomics.

This article presents an enhanced form of a novel bottom-up glycomics technique designed to analyze the pooled compositional profile of glycans in unfractionated biofluids through the chemical breakdown of glycans into their constituent linkage-specific monosaccharides for detection by GC-MS. Potential applications include early detection of cancer and other glycan-affective disorders.

Synthesized in a non-template-driven process by enzymes called glycosyltransferases, glycans are key players in various significant intra- and ...

Peptide and Protein Quantification Using Automated Immuno-MALDI (iMALDI)

Mass spectrometry (MS) is one of the most commonly used technologies for quantifying proteins in complex samples, with excellent assay specificity as a result of the direct detection of the mass-to-charge ratio of each target molecule. However, MS-based proteomics, like most other analytical techniques, has a bias towards measuring high-abundance analytes, so it is challenging to achieve detection limits of low ng/mL or pg/mL in complex samples, and this is the concentration range for many disease-relevant proteins in biofluids such as human plasma. To assist in the detection of low-abundance analytes, immuno-enrichment has been integrated into the assay to concentrate and purify the analyte before MS measurement, significantly improving assay sensitivity. In this work, the immuno- Matrix-Assisted Laser Desorption/Ionization (iMALDI) technology is presented for the quantification of proteins and peptides in biofluids, based on immuno-enrichment on beads, followed by MALDI-MS measurement without prior elution. The anti-peptide antibodies are functionalized on magnetic beads, and incubated with samples. After washing, the beads are directly transferred onto a MALDI target plate, and the signals are measured by a MALDI-Time of Flight (MALDI-TOF) instrument after the matrix solution has been applied to the beads. The sample preparation procedure is simplified compared to other immuno-MS assays, and the MALDI measurement is fast. The whole sample preparation is automated with a liquid handling system, with improved assay reproducibility and higher throughput. In this article, the iMALDI assay is used for determining the peptide angiotensin I (Ang I) concentration in plasma, which is used clinically as readout of plasma renin activity for the screening of primary aldosteronism (PA).

Peptide and Protein Quantification Using Automated Immuno-MALDI iMALDI

A protocol for the protein quantification in complex biological fluids using automated immuno-MALDI (iMALDI) technology is presented.

Mass spectrometry (MS) is one of the most commonly used technologies for quantifying proteins in complex samples, with excellent assay specificity as a ...

Rapid Nanoprobe Signal Enhancement by In Situ Gold Nanoparticle Synthesis

The use of nanoprobes such as gold, silver, silica or iron-oxide nanoparticles as detection reagents in bioanalytical assays can enable high sensitivity and convenient colorimetric readout. However, high densities of nanoparticles are typically needed for detection. The available synthesis-based enhancement protocols are either limited to gold and silver nanoparticles or rely on precise enzymatic control and optimization. Here, we present a protocol to enhance the colorimetric readout of gold, silver, silica, and iron oxide nanoprobes. It was observed that the colorimetric signal can be improved by up to a 10000-fold factor. The basis for such signal enhancement strategies is the chemical reduction of Au3+ to Au0. There are several chemical reactions that enable the reduction of Au3+ to Au0. In the protocol, Good&#39;s buffers and H2O2 are used and it is possible to favor the deposition of Au0 onto the surface of existing nanoprobes, in detriment of the formation of new gold nanoparticles. The protocol consists of the incubation of the microarray with a solution consisting of chloroauric acid and H2O2 in 2-(N-morpholino)ethanesulfonic acid pH 6 buffer following the nanoprobe-based detection assay. The enhancement solution can be applied to paper and glass-based sensors. Moreover, it can be used in commercially available immunoassays as demonstrated by the application of the method to a commercial allergen microarray. The signal development requires less than 5 min of incubation with the enhancement solution and the readout can be assessed by naked eye or low-end image acquisition devices such as a table-top scanner or a digital camera.

Rapid Nanoprobe Signal Enhancement by In Situ Gold Nanoparticle Synthesis

In this work, a protocol for signal enhancement of nanoprobe-based biosensing is presented. The protocol is based on the reduction of chloroauric acid onto the surface of existing nanoprobes that consist of gold, silver, silica or iron-oxide nanoparticles.

The use of nanoprobes such as gold, silver, silica or iron-oxide nanoparticles as detection reagents in bioanalytical assays can enable high sensitivity ...

Large-scale Top-down Proteomics Using Capillary Zone Electrophoresis Tandem Mass Spectrometry

Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) has been recognized as a useful tool for top-down proteomics that aims to characterize proteoforms in complex proteomes. However, the application of CZE-MS/MS for large-scale top-down proteomics has been impeded by the low sample-loading capacity and narrow separation window of CZE. Here, a protocol is described using CZE-MS/MS with a microliter-scale sample-loading volume and a 90-min separation window for large-scale top-down proteomics. The CZE-MS/MS platform is based on a linear polyacrylamide (LPA)-coated separation capillary with extremely low electroosmotic flow, a dynamic pH-junction-based online sample concentration method with a high efficiency for protein stacking, an electro-kinetically pumped sheath flow CE-MS interface with extremely high sensitivity, and an ion trap mass spectrometer with high mass resolution and scan speed. The platform can be used for the high-resolution characterization of simple intact protein samples and the large-scale characterization of proteoforms in various complex proteomes. As an example, a highly efficient separation of a standard protein mixture and a highly sensitive detection of many impurities using the platform is demonstrated. As another example, this platform can produce over 500 proteoform and 190 protein identifications from an Escherichia coli proteome in a single CZE-MS/MS run.

A detailed protocol is described for the separation, identification, and characterization of proteoforms in protein samples using capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS). The protocol can be used for the high-resolution characterization of proteoforms in simple protein samples and the large-scale identification of proteoforms in complex proteome samples.

Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) has been recognized as a useful tool for top-down ...

Solid Phase 11C-Methylation, Purification and Formulation for the Production of PET Tracers

Routine production of radiotracers used in positron emission tomography (PET) mostly relies on wet chemistry where the radioactive synthon reacts with a non-radioactive precursor in solution. This approach necessitates purification of the tracer by high performance liquid chromatography (HPLC) followed by reformulation in a biocompatible solvent for human administration. We recently developed a novel 11C-methylation approach for the highly efficient synthesis of carbon-11 labeled PET radiopharmaceuticals, taking advantage of solid phase cartridges as disposable &#34;3-in-1&#34; units for the synthesis, purification and reformulation of the tracers. This approach obviates the use of preparative HPLC and reduces the losses of the tracer in transfer lines and due to radioactive decay. Furthermore, the cartridge-based technique improves synthesis reliability, simplifies the automation process and facilitates compliance with the Good Manufacturing Practice (GMP) requirements. Here, we demonstrate this technique on the example of production of a PET tracer Pittsburgh compound B ([11C]PiB), a gold standard in vivo imaging agent for amyloid plaques in the human brains.

Solid Phase 11C-Methylation, Purification and Formulation for the Production of PET Tracers

We report an efficient carbon-11 radiolabeling technique to produce clinically relevant tracers for Positron Emission Tomography (PET) using solid phase extraction cartridges. 11C-methylating agent is passed through a cartridge preloaded with precursor and successive elution with aqueous ethanol provides chemically and radiochemically pure PET tracers in high radiochemical yields.

Routine production of radiotracers used in positron emission tomography (PET) mostly relies on wet chemistry where the radioactive synthon reacts with a ...