DETERMINATION OF THE ANOMERIC CONFIGURATION OF GLYCOSYL ESTERS OF NUCLEOSIDE PYROPHOSPHATES BY FAST-ATOM-BOMBARDMENT TANDEM MASS-SPECTROMETRY

Very low energy collision-induced dissociation of the deprotonated mol ecules of glycosyl esters of nucleoside pyrophosphates results in dist inct fragmentation patterns that depend on the cis-trans configuration of the phosphodiester and T-hydroxyl groups of the glycosyl residue. In tandem mass spectrometry, sugar nucleotides with cis configuration produce only one, very abundant fragment that corresponds to nucleosid e monophosphate, whereas nucleotides with trans configuration give wea k signals for the nucleoside di- and monophosphates and their dehydrat ion products. This empirical rule holds for sugar nucleotides that hav e a free 2 ''-hydroxyl group and no alternative charge location. Owing to its simplicity, sensitivity, and tolerance of impurities, fast-ato m bombardment-tandem mass spectrometry represents a suitable method fo r determination of the anomeric linkage of glycosyl esters of nucleosi de pyrophosphates if the absolute configuration of glycosyl residue is known and the compound fulfills the above-mentioned requirements.