{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T17:15:22Z","timestamp":1788455722121,"version":"build-2803163510"},"reference-count":11,"publisher":"American Chemical Society (ACS)","issue":"9","license":[{"start":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T00:00:00Z","timestamp":1786579200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"DOI":"10.13039\/na","name":"Laboratory of Biochemistry and Pharmacology, National Cancer Institute, U.S. National Institutes of Health","doi-asserted-by":"publisher","award":["Z01BJ02044-17LBP"],"award-info":[{"award-number":["Z01BJ02044-17LBP"]}],"id":[{"id":"10.13039\/na","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,9,2]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Permethylation is a widely used derivatization technique for mass spectrometry-based glycan analysis, applicable to both research and drug product characterization. It stabilizes sialic acids, improves glycan ionization, and is commonly used to analyze PNGase F-released N-linked glycans for distribution and composition profiling, yielding semiquantitative or quantitative data. We occasionally observed peaks 32 and 54 Da below expected ion masses, anomalies which are unreported in the literature. Investigation revealed these losses stem from slower-than-expected spontaneous exchange of C-1 amines for water in nascent glycosylamines following PNGase F release. Here, we report the origin of these mass losses, propose a mechanistic explanation, and suggest mitigation strategies.<\/jats:p>","DOI":"10.1021\/jasms.6c00173","type":"journal-article","created":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T19:02:29Z","timestamp":1786647749000},"page":"2251-2255","source":"Crossref","is-referenced-by-count":0,"title":["An Explanation for\nthe 32 and 54 Da Losses Seen in\n                    <i>N<\/i>\n                    -Linked Glycan\nPermethylation Reactions"],"prefix":"10.1021","volume":"37","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0176-426X","authenticated-orcid":true,"given":"Lisa M.","family":"Parsons","sequence":"first","affiliation":[{"name":"Food and Drug Administration, Center for Biologics Evaluation and Research, Division of Bacterial , Parasitic and Allergenic Products , , ,","place":["Silver Spring, Maryland, United States, 20993"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9663-8177","authenticated-orcid":true,"given":"John F.","family":"Cipollo","sequence":"additional","affiliation":[{"name":"Food and Drug Administration, Center for Biologics Evaluation and Research, Division of Bacterial , Parasitic and Allergenic Products , , ,","place":["Silver Spring, Maryland, United States, 20993"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2026,8,13]]},"reference":[{"issue":"2","key":"2026090311510914100_cit1","doi-asserted-by":"publisher","first-page":"147","DOI":"10.1016\/j.aca.2006.06.009","article-title":"Per-O-methylation\nreaction for structural analysis of carbohydrates by mass spectrometry","volume":"576","author":"Ciucanu","year":"2006","journal-title":"Anal. Chim. Acta"},{"issue":"2","key":"2026090311510914100_cit2","doi-asserted-by":"publisher","first-page":"628","DOI":"10.1016\/0003-9861(83)90561-1","article-title":"Oligosaccharides released from glycolipids\nby trifluoroacetolysis\ncan be analyzed by gas chromatography-mass spectrometry","volume":"222","author":"Nilsson","year":"1983","journal-title":"Arch. Biochem. Biophys."},{"issue":"2","key":"2026090311510914100_cit3","doi-asserted-by":"publisher","first-page":"209","DOI":"10.1016\/0008-6215(84)85242-8","article-title":"A simple and rapid method for the\npermethylation of carbohydrates","volume":"131","author":"Ciucanu","year":"1984","journal-title":"Carbohydr.\nRes."},{"issue":"52","key":"2026090311510914100_cit4","doi-asserted-by":"publisher","first-page":"16213","DOI":"10.1021\/ja035660t","article-title":"Elimination of Oxidative\nDegradation during the per-O-Methylation\nof Carbohydrates","volume":"125","author":"Ciucanu","year":"2003","journal-title":"J. Am. Chem. Soc."},{"issue":"17","key":"2026090311510914100_cit5","doi-asserted-by":"publisher","first-page":"10700","DOI":"10.1016\/S0021-9258(18)90568-5","article-title":"Demonstration\nof peptide:N-glycosidase\nF activity in endo-beta-N-acetylglucosaminidase F preparations","volume":"259","author":"Plummer","year":"1984","journal-title":"J. Biol. Chem."},{"issue":"2","key":"2026090311510914100_cit6","doi-asserted-by":"publisher","first-page":"vii","DOI":"10.1093\/glycob\/7.2.161-a","article-title":"Ammonium containing buffers should\nbe avoided during\nenzymatic release of glycans from glycoproteins when followed by reducing\nterminal derivatization","volume":"7","author":"Ku\u0308ster","year":"1997","journal-title":"Glycobiology"},{"key":"2026090311510914100_cit7","doi-asserted-by":"publisher","first-page":"44","DOI":"10.1016\/0076-6879(94)30006-2","article-title":"Enzymatic deglycosylation\nof asparagine-linked glycans:\npurification, properties, and specificity of oligosaccharide-cleaving\nenzymes from Flavobacterium meningosepticum","volume":"230","author":"Tarentino","year":"1994","journal-title":"Methods in Enzymology"},{"key":"2026090311510914100_cit8","doi-asserted-by":"publisher","first-page":"397","DOI":"10.1007\/BF01049915","article-title":"A systematic nomenclature\nfor fragmentatios in FAB-MS\/MS\nspectra of glycoconjugates","volume":"5","author":"Domon","year":"1988","journal-title":"Glycoconj J."},{"issue":"18","key":"2026090311510914100_cit9","doi-asserted-by":"publisher","first-page":"4895","DOI":"10.1021\/ac0341968","article-title":"Structural characterization of oligosaccharides\nusing MALDI-TOF\/TOF tandem mass spectrometry","volume":"75","author":"Mechref","year":"2003","journal-title":"Anal. Chem."},{"issue":"10","key":"2026090311510914100_cit10","doi-asserted-by":"publisher","first-page":"1799","DOI":"10.1016\/j.jasms.2007.07.016","article-title":"A glycomics platform for the analysis\nof permethylated oligosaccharide alditols","volume":"18","author":"Costell","year":"2007","journal-title":"J.\nAm. Soc. Mass Spectrom."},{"issue":"141","key":"2026090311510914100_cit11","doi-asserted-by":"publisher","first-page":"357","DOI":"10.1098\/rstl.1851.0017","article-title":"Researches\ninto the molecular constitution of the organic bases","author":"Hofmann","year":"1851","journal-title":"Philos. Trans. R. Soc. London"}],"container-title":["Journal of the American\nSociety for Mass Spectrometry"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pubs.acs.org\/doi\/pdf\/10.1021\/jasms.6c00173","content-type":"application\/pdf","content-version":"vor","intended-application":"unspecified"},{"URL":"https:\/\/pubs.acs.org\/jamsef\/article-pdf\/37\/9\/2251\/66535077\/jasms.6c00173.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pubs.acs.org\/jamsef\/article-pdf\/37\/9\/2251\/66535077\/jasms.6c00173.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T16:22:26Z","timestamp":1788452546000},"score":1,"resource":{"primary":{"URL":"https:\/\/pubs.acs.org\/jamsef\/article\/37\/9\/2251\/5254788\/An-Explanation-for-the-32-and-54-Da-Losses-Seen-in"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,13]]},"references-count":11,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2026,8,13]]},"published-print":{"date-parts":[[2026,9,2]]}},"URL":"https:\/\/doi.org\/10.1021\/jasms.6c00173","relation":{},"ISSN":["1044-0305","1879-1123"],"issn-type":[{"value":"1044-0305","type":"print"},{"value":"1879-1123","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,13]]}}}