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J Am Soc Mass Spectrom

Title:		Mass spectrometry combinations for structural characterization of sulfated-steroid metabolites
Author(s):		Yan Y; Rempel DL; Holy TE; Gross ML;
Address:
Journal Title:		J Am Soc Mass Spectrom
Year:		2014
Volume:		25
Issue:		5
Page Number:		869 - 879
DOI:		10.1007/s13361-014-0836-9
ISSN/ISBN:		1879-1123 (Electronic) 1044-0305 (Print) 1044-0305 (Linking)
Abstract:		"Steroid conjugates, which often occur as metabolites, are challenging to characterize. One application is female-mouse urine, where steroid conjugates serve as important ligands for the pheromone-sensing neurons. Although the two with the highest abundance in mouse urine were previously characterized with mass spectrometry (MS) and NMR to be sulfated steroids, many more exist but remain structurally unresolved. Given that their physical and chemical properties are similar, they are likely to have a sulfated steroid ring structure. Because these compounds occur in trace amounts in mouse urine and elsewhere, their characterization by NMR will be difficult. Thus, MS methods become the primary approach for determining structure. Here, we show that a combination of MS tools is effective for determining the structures of sulfated steroids. Using 4-pregnene analogs, we explored high-resolving power MS (HR-MS) to determine chemical formulae; HD exchange MS (HDX-MS) to determine number of active, exchangeable hydrogens (e.g., OH groups); methoxyamine hydrochloride (MOX) derivatization MS, or reactive desorption electrospray ionization with hydroxylamine to determine the number of carbonyl groups; and tandem MS (MS(n)), high-resolution tandem MS (HRMS/MS), and GC-MS to obtain structural details of the steroid ring. From the fragmentation studies, we deduced three major fragmentation rules for this class of sulfated steroids. We also show that a combined MS approach is effective for determining structure of steroid metabolites, with important implications for targeted metabolomics in general and for the study of mouse social communication in particular"
Keywords:		Analytic Sample Preparation Methods Animals Female Gas Chromatography-Mass Spectrometry Hydrocortisone/*analogs & derivatives/chemistry/metabolism Hydroxylamines/chemistry Indicators and Reagents/chemistry Mice Molecular Structure Molecular Weight Pregnen;
Notes:		"MedlineYan, Yuetian Rempel, Don L Holy, Timothy E Gross, Michael L eng P41 GM103422/GM/NIGMS NIH HHS/ R01 DC005964/DC/NIDCD NIH HHS/ 8 P41 GM103422-35/GM/NIGMS NIH HHS/ Research Support, N.I.H., Extramural 2014/03/25 J Am Soc Mass Spectrom. 2014 May; 25(5):869-79. doi: 10.1007/s13361-014-0836-9"