Normalized Labeling

Found in PeakGroups

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The enrichment in this compound normalized to the enrichment in the tracer compound(s) from the final serum timepoint for that animal. This is calculated for each labeled element separately.

Normalized Labeling = ThisPeakGroup.enrichment_fraction / SerumTracerPeakGroup.enrichment_fraction

Example: normalized labeling in alanine (C3H7NO2) and glutamate (C5H9NO4) measured in the final serum sample and one tissue (quadricep) sample from an infusion of [13C3-15N]-alanine:

Tissue	Measured Compound(s)	Labeled Element	Total Abundance	Enrichment Fraction	Enrichment Abundance	Normalized Labeling
serum_plasma_tail	alanine	C	1721209	0.275916	474909.5	1
serum_plasma_tail	alanine	N	1721209	0.344919	593677.6	1
serum_plasma_tail	glutamate	C	242215.7	0.018	4359.787	0.065236
serum_plasma_tail	glutamate	N	242215.7	0.053935	13063.83	0.156369
quadricep	alanine	C	97694902	0.006183	604078.4	0.02241
quadricep	alanine	N	97694902	0.019993	1953218	0.057964
quadricep	glutamate	C	14251992	0.007268	103580.9	0.026341
quadricep	glutamate	N	14251992	0.087257	1243586	0.252978

In some cases, a labeled element present in a tracer is not found in a measured compound, and Normalized Labeling is not reported. For example, lactate (C3H6O3) can be measured in samples from an animal infused with N-labeled glutamine (C5H10N2O3), but no nitrogen enrichment or normalized labeling is reported for lactate.

For infusates with multiple tracers, SerumTracerPeakGroup.enrichment_fraction = average of enrichment in each serum tracer group.

The SerumTracerPeakGroup depends on some edge cases:

• if two serum samples were collected on the same date and same minutes after the start of infusion, (ie they are biological replicates), the specific value selected is arbitrary.
• if the same SerumTracerPeakGroup is repeated in multiple MSruns (appears in multiple accucor files), the most recent uploaded data is selected.