Metabolic Flux

Isotope tracers are essential tools for monitoring metabolic pathway activity, i.e. flux. To quantitate flux in central carbon metabolism in cultured mammalian cells, D-glucose (13C6, 99%) (CLM-1396) or L-glutamine (13C5, 99%) (CLM-1822) is added to media lacking these principal nutrients. Cells are grown in the labeled media, and. metabolite labeling is measured by GC-MS or LC-MS. Glucose has traditionally been considered to be the primary carbon source for many cell types, especially cancer cells. Recent studies show, however, the glutamine often plays a predominant role in feeding the tricarboxylic acid (TCA) cycle. The extent of contribution of glutamine to TCA cycle four-carbon units can be measured based on malate and asparate labeling, and to two-carbon units based on acetyl-CoA and fatty acid labeling. Citrate is a particularly informative molecule, because it reflects both two- and four-carbon units of the TCA cycle. With modern instrumentation, it is possible to measure in parallel the isotope labeling of all of these species, and dozens more, enabling systems-level flux quantitation. These methods can translate also to the in vivo setting, with mice or patients infused with labeled nutrients prior to resection of a tumor or other tissue specimen. The importance of metabolism in both bioengineering and disease pathophysiology is leading to wide application of these methods across the biochemical sciences.

Cellular Metabolism and Metabolomics

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Frequently Asked Questions

What is 13C-MFA? 13C-MFA or 13C metabolic flux analysis is a stable isotope-assisted technique that is the gold standard for accurate and precise flux determination. Flux can be inferred utilizing stable isotope-labeled tracers in combination with mass spectrometry (MS) or nuclear magnetic resonance (NMR).

Does CIL offer different grades of products for metabolic flux analysis? Yes, CIL provides additional testing on many of our products as a service to our customers. Please view the Product Quality Designation chart for a description of the different grades.

When are CIL’s -MPT products tested for microbiological content? They are tested in the bulk form at release. Subsequent aliquots are not retested and guaranteed upon receipt of order. Microbiological testing does not imply suitability for any intended use.

Does CIL offer products for clinical trials? Yes, CIL can produce cGMP-grade material that is suitable for clinical trials. Please contact us to discuss your project.

Example Reference

Antoniewicz, M.R. 2021. A guide to metabolic flux analysis in metabolic engineering: Methods, tools and applications. Metab Eng, 63, 2-12. Read more.