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United States Department of Agriculture

Agricultural Research Service

Title: Acylic Sugar Derivatives for Gc-Ms Analysis of **13c-Enrichment During Carbohydrate Metabolism

Author
item Price, Neil

Submitted to: Analytical Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 9, 2004
Publication Date: November 15, 2004
Citation: Price, N.P. 2004. Acylic sugar derivatives for GC-MS analysis of **13C-enrichment during carbohydrate metabolism. Analytical Chemistry. 76:6566-6574.

Interpretive Summary: Understanding how animals metabolize feed and nutrients is important as a potential indicator of healthiness. This can be achieved by assessing the rate of metabolic turnover (flux) of carbohydrates in animal tissue or waste using a technique known as isotopic-enrichment mass spectrometry. This paper compares several sugar derivatives useful for measuring metabolic rates and for tracing the biological routes of carbohydrate metabolism. A broad spectrum of carbohydrates was assessed, providing data useful for lab-based veterinary testing. During the course of this work, a new series of sugar derivative was discovered with novel properties that greatly expand the potential for this type of metabolic analysis. These new techniques, in combination with existing methods, will facilitate the quantitative analysis of turnover rates in animal metabolism as a potential litmus-test of fitness and general healthiness. Applications are expected in animal husbandry, as a potential indicator of the quality of dairy, poultry, and meat products.

Technical Abstract: Metabolic profiling with stable-isotope tracers in combination with gas chromatography-mass spectrometry (GC-MS) is a well-established technique for measuring substrate redistribution within metabolic pathways. This analysis relies on the ability to localize and quantify the fractional incorporation of **13C-isotope into each carbon atom of precursor-derived metabolites. In this paper, several carbohydrate derivatization procedures (peracetylation, deutero-alditol acetates, and aldononitrile acetates) are evaluated for the positional isotopic information obtained by gas chromatography-electron impact mass spectrometry (GC-MS). These derivatives have been compared for the quantitative evaluation of **13C distribution into isotopomers of **13C-labeled aldoses and ketoses, and the fragmentation pathways for 15 hexoses, pentoses, and amino sugars of biological origin have been assessed. In addition, a new type of carbohydrate derivative (dialkyldithioacetal acetates) has been developed for GC-MS that retains the charge on the anomeric carbon of the original monosaccharide. Electron impact ionization of these derivatives generates well-resolved base peaks arising from C1-C2 bond cleavage with charge retention at the C1 thiol groups. The dialkyldithioacetal acetates are uniquely well-suited for measuring isotopic enrichment into the characteristic anomeric carbon of aldose sugars and will facilitate the global analysis of metabolic flux in carbohydrate pathways.

Last Modified: 4/18/2014