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Xuntian Jiang - One of the best experts on this subject based on the ideXlab platform.
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characterization of oxysterols by electrospray ionization tandem mass spectrometry after one step derivatization with dimethylglycine
Rapid Communications in Mass Spectrometry, 2007Co-Authors: Xuntian JiangAbstract:: We report a novel approach to derivatize the primary, secondary, and tertiary hydroxy group(s) of oxysterols with N,N-dimethylglycine (DMG) in the presence of both 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 4-(N,N-dimethylamino)pyridine to yield their corresponding mono- or di-DMG esters. Eight oxysterols including 7-oxocholesterol, 5alpha,6alpha- and 5beta,6beta-epoxycholesterols, as well as 7alpha-, 7beta-, 24(S)-, 25-, and 27-hydroxycholesterols, were studied. Electrospray ionization tandem mass spectrometric characterization of these singly or doubly protonated derivatives demonstrates the presence of an informative fragmentation pattern for each oxysterol derivative. Potential dissociation pathways for the production of these unique fragmentation patterns are proposed and discussed. Collectively, these informative and unique fragmentation patterns allow rapid and Direct Discrimination of the identities of 7alpha-, 7beta-, 24(S)-, 25-, and 27-hydroxycholesterol isomers, as well as 5alpha,6alpha- and 5beta,6beta-epoxycholesterol isomers, thereby potentially providing a foundation for quantitative analysis of oxysterols in biological samples in combination with a chromatographic separation.
Richard W Gross - One of the best experts on this subject based on the ideXlab platform.
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structural determination of lysophospholipid regioisomers by electrospray ionization tandem mass spectrometry
Journal of the American Chemical Society, 1996Co-Authors: Xianlin Han, Richard W GrossAbstract:The facile structural determination of lysophospholipid regioisomers represents a long-standing problem in phospholipid chemistry. Herein we report that positive-ion electrospray ionization (ESI) tandem mass spectrometry of sodiated lysophospholipid regioisomers results in the presence of multiple diagnostic pairs of product ions which allows the rapid and Direct Discrimination between sn-1-acyl- and sn-2-acyllysophospholipid regioisomers. For example, after ESI in the positive-ion mode and subsequent collision-induced dissociation, over a 30-fold difference in the peak intensity ratio of product ions at m/z 104 and 147 was manifest with sodiated sn-1-acyllysophosphatidylcholine in comparison to sn-2-acyllysophosphatidylcholine. The observed differences in precursor ion dissociation rates reflect both the kinetically favored formation of a 5-membered phosphodiester (compared to the corresponding 6-membered phosphodiester) and the accelerated rate of an activated vs a nonactivated rearrangement. The struct...
Wang, Peng George - One of the best experts on this subject based on the ideXlab platform.
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Sialic acid linkage-specific permethylation for improved profiling of protein glycosylation by MALDI-TOF MS
ANALYTICA CHIMICA ACTA, 2017Co-Authors: Jiang Kuan, He Zhu, Li Lei, Guo Yuxi, Gashash Ebtesam, Ma Cheng, Sun Xiaolin, Li Jing, Zhang Lianwen, Wang, Peng GeorgeAbstract:Protein glycosylation mediates a wide range of cellular processes, affecting development and disease in mammals. Deciphering the "glycocodes" requires rapid, sensitive and in-depth characterization of diverse glycan structures derived from biological samples. In this study, we described a two-step derivatization strategy termed linkage-specific sialic acid permethylation (SSAP) consisting of dimethylamination and permethylation for the improved profiling of glycosylation by matrix-assisted laser desorption/ionization (MALDI) time-of-fight (TOF) mass spectrometry (MS). High linkage-specificity (similar to 99%) of SSAP to both the two most common forms of sialic acid, N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc), permitted Direct Discrimination of alpha 2,3- and alpha 2,6-linked sialic acids in MALDI-TOF MS. The enhanced intensity (> 10-fold) and increased detection limit (> 10-fold) of derivatized glycans were valued for sensitive glycomics. Moreover, the good compatibility and reaction efficiency of the two steps of SSAP allowed rapid sample preparation (< 2 h), benefiting robust analysis of glycans in a high-throughput manner. The SSAP strategy was further applied to investigate the protein glycosylation of human serum associated with rheumatoid arthritis (RA). It was demonstrated that the relative abundances of individual glycans were different in RA negative and RA positive samples, and meanwhile the RA patient/control ratios of both alpha 2,3- and alpha 2,6-sialylated glycans tended to elevate accompanied with the increase of sialylation. Those findings of the glycosylation changes occurred in human serum protein may contribute to the diagnosis of RA. Herein, SSAP derivatization combined with MALDI-TOF MS exhibits unique advantages for glycomic analysis and shows potential in glycosylation profiling of therapeutic proteins and clinical glycan biomarker discovery. (C) 2017 Elsevier B.V. All rights reserved.National Institutes of Health [U01GM116263]; National Natural Science Foundation of China [31470795, 31000371, 21372130]; Tianjin Municipal Science and Technology Commission [15JCYBJC24100, 15JCYBJC29000]; China Scholarship Council [201506200006]SCI(E)ARTICLE53-6198
Xianlin Han - One of the best experts on this subject based on the ideXlab platform.
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structural determination of lysophospholipid regioisomers by electrospray ionization tandem mass spectrometry
Journal of the American Chemical Society, 1996Co-Authors: Xianlin Han, Richard W GrossAbstract:The facile structural determination of lysophospholipid regioisomers represents a long-standing problem in phospholipid chemistry. Herein we report that positive-ion electrospray ionization (ESI) tandem mass spectrometry of sodiated lysophospholipid regioisomers results in the presence of multiple diagnostic pairs of product ions which allows the rapid and Direct Discrimination between sn-1-acyl- and sn-2-acyllysophospholipid regioisomers. For example, after ESI in the positive-ion mode and subsequent collision-induced dissociation, over a 30-fold difference in the peak intensity ratio of product ions at m/z 104 and 147 was manifest with sodiated sn-1-acyllysophosphatidylcholine in comparison to sn-2-acyllysophosphatidylcholine. The observed differences in precursor ion dissociation rates reflect both the kinetically favored formation of a 5-membered phosphodiester (compared to the corresponding 6-membered phosphodiester) and the accelerated rate of an activated vs a nonactivated rearrangement. The struct...
Rosario Martín - One of the best experts on this subject based on the ideXlab platform.
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differentiation of european wild boar sus scrofa scrofa and domestic swine sus scrofa domestica meats by pcr analysis targeting the mitochondrial d loop and the nuclear melanocortin receptor 1 mc1r genes
Meat Science, 2008Co-Authors: Violeta Fajardo, Mari A Rojas, Teresa Garci A, Irene Martinez Martin, Isabel Gonzalez, Pablo E. Hernández, Rosario MartínAbstract:Abstract This work describes the differentiation of European wild boar ( Sus scrofa scrofa ) and domestic swine ( Sus scrofa domestica ) meats by PCR targeting sequences from two molecular markers: the mitochondrial displacement loop (D-loop) region and the nuclear melanocortin receptor 1 ( MC1R ) gene. A polymorphic D-loop fragment (∼270 bp) was amplified and sequenced in a number of wild and domestic Sus scrofa meat samples, to find a nucleotide region suitable for PCR–RFLP analysis. Sequence data showed the presence of only a few point mutations across Sus scrofa D-loop sequences, not allowing Direct Discrimination between wild boar and domestic swine meats. Later, the MC1R gene was targeted and Sus scrofa -specific primers designed to amplify a 795 bp MC1R fragment. Subsequent RFLP analysis of the MC1R swine-specific amplicons allowed selection of BspHI and BstUI endonucleases to carry out intraspecific Sus scrofa differentiation. Digestion of MC1R amplicons with the chosen enzymes generated characteristic PCR–RFLP profiles that allowed Discrimination among meats from wild and domestic swine specimens. The technique also enabled the detection of samples that yielded heterozygous profiles, suggesting hybrids resulting from wild boar and domestic pig breeding. The PCR–RFLP reported here, targeting the MC1R gene may be routinely applied to verify the correct labelling of game products.