Dr. Lingjun Li

Lingjun received her BE degree in Environmental Analytical Chemistry from Beijing Polytechnic University and a PhD degree in Analytical Chemistry/Biomolecular Chemistry from University of Illinois at Urbana-Champaign. She did three-way postdoctoral research at the Pacific Northwest National Laboratory, Brandeis University, and University of Illinois before joining the School of Pharmacy faculty in 2002. She currently holds joint appointments in the School of Pharmacy and Department of Chemistry at UW-Madison, as well as being named Charles Melbourne Johnson Distinguished Chair and Vilas Distinguished Achievement Professor.

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Enrichment and fragmentation approaches for enhanced detection and characterization of endogenous glycosylated neuropeptides

Proteomics

Glycosylated neuropeptides were recently discovered in crustaceans, a model organism with a well-characterized neuroendocrine system. Several workflows exist to characterize enzymatically digested peptides; however, the unique properties of endogenous neuropeptides require methods to be re-evaluated. We evaluate the use of hydrophilic interaction liquid chromatography (HILIC) enrichment and different fragmentation methods to further probe the expression of glycosylated neuropeptides in Callinectes sapidus. During the evaluation of HILIC, we observed the necessity of a less...

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Recent advances in isobaric labeling and applications in quantitative proteomics

Proteomics

Mass spectrometry (MS) has emerged at the forefront of quantitative proteomic techniques. Liquid chromatography-mass spectrometry (LC-MS) can be used to determine abundances of proteins and peptides in complex biological samples. Several methods have been developed and adapted for accurate quantification based on chemical isotopic labeling. Among various chemical isotopic labeling techniques, isobaric tagging approaches rely on the analysis of peptides from MS2-based quantification rather than MS1-based quantification. In this review, we will provide an overview of several isobaric tags along with...

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Simultaneous multiplexed quantification and C=C localization of fatty acids with LC-MS/MS using isobaric multiplex reagents for carbonyl-containing compound (SUGAR) tags and C=C epoxidation

Analytical Chemica Acta

Fatty acids (FAs) possess highly diverse structures and can be divided into saturated and unsaturated classes. For unsaturated FAs, both the numbers and positions of carbon-carbon double bond (C=C) determine their biological functions. Abnormal levels of FA isomers have been reported to be involved in various disease development, such as cancer. Despite numerous advances in lipidomics, simultaneous quantifying and pinpointing C=C bond positions in a high-throughput manner remains a challenge. Here we conducted epoxidation of C=C bonds of unsaturated FAs...