---
title: "Metabolic Flux & Isotope Tracing"
lang: en
url: https://www.gereallife.com/en/services/metabolic-flux.html
canonical: https://www.gereallife.com/en/services/metabolic-flux.html
entity: Shanghai Gereallife Biotech Co., Ltd
updated: 2026-11-02
---
ISOTOPE TRACING 
 

# Metabolic Flux & Isotope Tracing

 

Stable Isotope Tracing — Quantify Flux, Not Just Abundance

 

Isotope-tracing metabolic flux analysis feeds cells or infuses animals with stable-isotope (¹³C / ¹⁵N) labeled substrates; once the label incorporates into downstream metabolites, mass spectrometry measures their mass isotopomer distributions (MID) and positional isotopomers — isotopomer patterns carry far more pathway information than concentrations alone: conventional metabolomics answers "how much", while flux analysis answers "where from, where to, and via which route". Single tracers reveal pathways through isotopomer ratios; parallel multi-tracer designs quantify absolute fluxes; positional isotopomers resolve metabolic branch points. The workflow runs "labeled-substrate incubation → MS detection of MID → natural-abundance correction → metabolic network modeling". Tracer choice directly determines which pathways can be resolved and must be fixed during study design together with the research question.

 
 
 13C / 15N Stable-Isotope Tracing STABLE ISOTOPE TRACING 6 Traceable Pathways TRACER PATHWAYS 4–6 weeks Standard Turnaround PROJECT CYCLE 

## Specifications & Samples

 TECHNICAL SPECIFICATIONS 

| Item | Details |
| --- | --- |
| Platform | Q Exactive high-resolution MS with polarity switching and isotopomer-resolved acquisition; complementary GC-MS / LC-MS dual platforms |
| Samples & Systems | In vitro cell models (tumor, primary, stem cells) · in vivo animal models · microbial fermentation systems · plant tissues · plasma and other biofluids; after labeling, snap-freeze samples in liquid nitrogen and ship on dry ice |
| Deliverables & Timeline | Statistics tables · MID tables · analysis report; standard turnaround 4–6 weeks |
| Information to Confirm | Research background and questions · sample types and comparison design · target pathways · expected sample size and labeled substrates |

 
 

## Workflow

 SERVICE WORKFLOW 1 Labeled Incubation Switch to isotope medium at steady state 2 MS Detection of MID GC-MS / LC-MS dual platforms 3 Natural-Abundance Correction Subtract natural-isotope background 4 Network Modeling Flux estimation (when applicable) 5 Statistics & Visualization Flux maps, heatmaps & interpretation Study-design support: full support for ¹³C / ¹⁵N tracer selection and sourcing, labeling dose and duration, and sampling time-point design — controlling tracing costs while keeping fluxes measurable. 
 

## Traceable Pathways & Representative Tracers

 TRACER PATHWAYS 

| Pathway | Common Tracers / Representative Substrates · Resolvable Readouts |
| --- | --- |
| 1 · Glucose Flux GLUCOSE FLUX | [U-¹³C]glucose / [1,2-¹³C]glucose / [1,6-¹³C]glucose / [2,3-¹³C]glucose — flux partitioning among glycolysis, the TCA cycle and the pentose phosphate pathway; [1,6-¹³C] and [2,3-¹³C] distinguish PPP branches and PDH activity; Warburg-effect quantification in tumors and proliferating cells |
| 2 · Fatty Acid Flux FATTY ACID FLUX | [U-¹³C]acetate / [U-¹³C]palmitate — relative contributions of de novo lipogenesis (DNL) versus exogenous uptake; acetyl-CoA pools and fatty-acid β-oxidation; chain elongation and desaturation fates |
| 3 · Nucleotide Flux NUCLEOTIDE FLUX | [U-¹³C]nucleosides/nucleotides / [¹⁵N4]hypoxanthine — balance between de novo and salvage synthesis of purines/pyrimidines; resolving the sources of proliferation-driven nucleotide demand |
| 4 · Amino Acid Flux AMINO ACID FLUX | [U-¹³C]glutamine / [amide-¹⁵N]glutamine / [U-¹³C]serine — nitrogen flow through glutaminolysis, TCA anaplerosis and transamination; carbon-skeleton exchange among amino acids |
| 5 · Folate / One-Carbon Flux ONE-CARBON FLUX | [U-¹³C]serine / [U-¹³C]glycine — carbon-source assignment for one-carbon units, purine synthesis and methylation; folate-cycle efficiency assessment |
| 6 · Urea Cycle Flux UREA CYCLE FLUX | ¹⁵N-NH₄Cl / [amide-¹⁵N]glutamine — nitrogen metabolism and urea-cycle flux; ammonia-clearance efficiency and ¹⁵N fate in purine synthesis |

 
 

## Bioinformatics Analyses

 BIOINFORMATIC MODULES 

| Module | Methods & Metrics · Key Outputs |
| --- | --- |
| Data Preprocessing | Metabolite peak extraction and integration, mass-isotopomer (M+0 / M+1 / M+2 …) signal extraction, sample naming and group mapping, low-quality peak filtering — raw and corrected MID data tables |
| Natural-Abundance Correction | Matrix-based subtraction of natural ¹³C / ¹⁵N / ¹⁸O / ²H backgrounds; correction quality assessed by residual RMS — RMS bar charts, before/after comparison plots |
| Labeling Overview | Labeling rate (enrichment) = weighted mean labeling across m+ isotopologues; group-mean comparison and inter-sample correlation matrix — labeling-rate heatmap, group-mean bar charts |
| MID Composition | Inter-sample isotope-ratio distributions, intra-sample m+ distributions, group MID composition comparison (mean ± SD) — distribution plot sets, MID composition tables |
| Group Comparisons & Cross-Comparison Summary | Independent statistics per comparison (labeling-rate differences, differential MIDs); cross-comparison summary heatmaps and Venn diagrams — differential labeled-metabolite lists and intersection lists |

 
 

## Example Results

 SELECTED FIGURES FROM ACTUAL REPORTS Calibration Residual (RMS) Bar Chart Natural-abundance correction residuals per metabolite — smaller RMS indicates more reliable correction. Group-Mean Labeling-Rate Bar Chart Comparison of mean labeling rates (enrichment) across groups, outlining intergroup flux differences. Differential MID Heatmap Clustered heatmap of m+ fractions for differential metabolites; red/blue encodes direction and magnitude of labeling differences. Labeling-Rate Heatmap Metabolite × sample labeling-rate matrix for quickly locating highly labeled pathways and outlier samples. KEGG Pathway Proportion Analysis KEGG level-3 pathway proportions of detected labeled metabolites, clarifying flux-coverage scope. Intra-Sample Isotope Distribution m+ composition of each metabolite within a single sample — the basic unit of readout. Inter-Sample Isotope-Ratio Distribution Distribution of m+ ratios across samples, assessing whether labeling has reached steady state. Group MID Composition Comparison Stacked comparison of group MID means ± SD, comparing label propagation along pathways. Labeling-Rate Difference Bar Chart Labeling-rate differences and significance for specified comparisons, screening differential labeled metabolites. 
 

## Applications

 APPLICATIONS 
 Tumor Metabolic Reprogramming Glycolysis / TCA Cycle Flux Isotope-Tracer Fate Mapping Cellular Energy Metabolism Drug Metabolism Mechanisms 
 

## FAQ

 FAQ 
 How long does a Metabolic Flux & Isotope Tracing project take? Mature targeted panels typically take 1-3 weeks; untargeted projects take 2-4 weeks (counted from sample receipt and QC approval). The exact timeline is confirmed in writing before project start, and progress is trackable on the OmicsHub cloud platform. What if my sample amount is below the recommendation? Please do not dilute your samples. Low-input samples can often be accommodated by adjusting the preparation workflow — tell us the actual amount and our technical team will assess feasibility and note adjustments in the study plan. Can I add targets to an existing panel? Yes. Mature panels support on-demand additions; novel analytes outside the list can be implemented through custom method development (requires standards and extra validation time) — see our Custom Targeted Metabolomics service. What samples do you need for Metabolic Flux & Isotope Tracing? Serum/plasma ≥100 μL (fasting, no haemolysis), tissue ≥50 mg (snap-frozen), cells ≥1×10⁶ (medium washed off), urine ≥200 μL. Keep fasting time consistent, aliquot into single-use volumes and avoid freeze–thaw. Full guidance: Technical Resources → Sample Guide . 
 
 

## Related Services

 RELATED SERVICES 
 

### Targeted Metabolomics

Targeted Metabolomics

 

### Environmental Exposomics

Environmental Exposomics

 

### Untargeted Metabolomics

Untargeted Metabolomics

 
 
 

Delivery timing: sample shipping, customs declaration and similar steps may extend turnaround; actual project timelines prevail.

 
 
 
 

## Request a Quote or Study Design

Tell us about your project — we reply within one business day (free assessment)

 
 
 
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