title: Mass spectrometric analysis of sialylated glycans with use of solid-phase labeling of sialic acids.
abstract: The analysis of sialylated glycans is critical for understanding the role of sialic acid in normal biological processes as well as in disease. However, the labile nature of sialic acid typically renders routine analysis of this monosaccharide by mass spectrometric methods difficult. To overcome this difficulty we pursued derivatization methodologies, extending established acetohydrazide approaches to aniline-based methods, and finally to optimized p-toluidine derivatization. This new quantitative glycoform profiling method with use of MALDI-TOF in positive ion mode was validated by first comparing N-glycans isolated from fetuin and serum and was then exploited to analyze the effects of increased metabolic flux through the sialic acid pathway in SW1990 pancreatic cancer cells by using a colabeling strategy with light and heavy toluidine. The latter results established that metabolic flux, in a complementary manner to the more well-known impact of sialyltransferase expression, can critically modulate the sialylation of specific glycans while leaving others virtually unchanged.
authors: Department of Pathology, Johns Hopkins University, Baltimore, Maryland 21231, United States.
authors: Punit
authors: P
authors: Shah
authors: Shuang
authors: S
authors: Yang
authors: Shisheng
authors: S
authors: Sun
authors: Paul
authors: P
authors: Aiyetan
authors: Kevin J
authors: KJ
authors: Yarema
authors: Hui
authors: H
authors: Zhang
mesh_terms: D000818:Animals; D002417:Cattle; D045744:Cell Line, Tumor; D060748:Fetuins / Q000737:chemistry; D006801:Humans; D011134:Polysaccharides / Q000737:chemistry*; D044967:Serum / Q000737:chemistry; D012794:Sialic Acids / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D060748:Fetuins; D011134:Polysaccharides; D012794:Sialic Acids