PeakGroups

PeakGroups report the abundance and enrichment summated from each isotope associated with a measured compound (as listed in PeakData). Thus, they report values for the entire "group" of peaks for each compound.

PeakGroup values are almost always reported in a single row for each observed compound. Multiple PeakGroups rows are generated when the animal was infused with a tracer(s) that contains multiple labeled elements. For example, a mouse could be infused with a single amino acid labeled with both 13C and 15N. In this case, TraceBase reports a separate PeakGroup for each labeled element. This ensures that PeakGroups are always comparable between experiments, even when comparing a mouse infused with 13C-15N tracers to a mouse given only 13C. Any analysis that relies on considering both labeled elements simultaneously can be performed on PeakData.

See this example for a measured compound with multiple labeled elements.

Some key values reported in PeakGroups are:

• Total Abundance
• Enrichment Fraction
• Enrichment Abundance
• Normalized Labeling

Downloaded PeakGroups data has a standard format.