Tandem mass spectrometry for measuring stable-isotope labeling.

Measuring metabolic rates by (13)C-metabolic flux analysis ((13)C-MFA) is of central importance for metabolic engineers and biomedical investigators. Enhanced knowledge of in vivo fluxes can be applied to reengineer the metabolic, regulatory, and phenotypic characteristics of organisms and help uncover the mechanisms of human ailments such as cancer and diabetes. To determine accurate and precise fluxes by (13)C-MFA advanced methods for measuring stable-isotope labeling are needed. The application of tandem mass spectrometry is emerging as a new promising technique that has significant advantages over traditional MS and NMR based methods. With further refinement, tandem MS has the potential to become the new gold standard for measuring isotopic labeling for (13)C-flux studies.