David Scott focuses on the development and application of methods for metabolomics, enhanced by the use of stable isotope substrates. Stable isotopes (mainly 13C) provide an added layer of information to metabolomic studies – not only is static pool information obtained, but it is also possible to infer the origins of metabolites and to track flux through metabolic pathways. Methods used include the analysis of small polar metabolites (mainly amino acids and carboxylic acids) and fatty acids by gas chromatography-mass spectrometry.
Other techniques are being developed to analyze and quantify an expanded range of (labeled) metabolites. We have applied these methods in a study of the central carbon metabolism in Escherichia coli, and, in several papers, on melanoma metabolism. Investigations of melanoma cells showed the importance of glutamine metabolism under hypoxia, identified a novel route for the utilization of the carbon backbone of glutamine for fatty acid synthesis, and defined pathways for proline synthesis. Other recent work uses alternately labeled sugars to simultaneously track different inputs to glycans in normal cells and cell lines from patients with glycosylation defects.