Quantification and Mass Isotopomer Profiling of α-Keto Acids in Central Carbon Metabolism
作者:Michael Zimmermann、Uwe Sauer、Nicola Zamboni
DOI:10.1021/ac500472c
日期:2014.3.18
Mass spectrometry has been established as a powerful and versatile technique for studying cellular metabolism. Applications range from profiling of metabolites to accurate quantification and tracing of stable isotopes through the biochemical reaction network. Despite broad coverage of central carbon metabolism, most methods fail to provide accurate assessments of the α-keto acids oxaloacetic acid, pyruvate, and glyoxylate because these compounds are highly reactive and degraded during sample processing and mass spectrometric measurement. We present a derivatization procedure to chemically stabilize these compounds readily during quenching of cellular metabolism. Stable derivatives were analyzed by ultrahigh pressure liquid chromatography coupled tandem mass spectrometry to accurately quantify the abundance of α-keto acids in biological matrices. Eventually, we demonstrated that the developed protocol is suited to measure mass isotopomers of these α-keto acids in tracer studies with stable isotopes. In conclusion, the here described method fills one of the last technical gaps for metabolomics investigations of central carbon metabolism.
Chemoenzymatic synthesis of GM3, Lewis x and sialyl Lewis x oligosaccharides in 13C-enriched form
作者:Mark A. Probert、Mark.J. Milton、Richard Harris、Sergio Schenkman、Jonathan M. Brown、Steven W. Homans、Robert A. Field
DOI:10.1016/s0040-4039(97)01304-x
日期:1997.8
In connection with studies on the solution and protein-bound conformation of oligosaccharides, we had reason to consider the application of C-13-enriched sugars. Herein we describe the synthesis of ganglioside GM(3) trisaccharide (1), Lewis x trisaccharide (2) and the sialyl Lewis x tetrasaccharide (3) from [U-C-13]-D-Glc, [U-C-13]-L-Gal and [U-C-13]-pyruvate. (C) 1997 Elsevier Science Ltd.
We report on a strategy for the “turn-on” detection of targetbiochemical (metabolic) reactions using a triple resonance NMR technique with an isotope-labeled probe. Our NMR study clearly reveals t...