Metabolic Flux & Isotope Tracing

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

Labeled Incubation

Switch to isotope medium at steady state

MS Detection of MID

GC-MS / LC-MS dual platforms

Natural-Abundance Correction

Subtract natural-isotope background

Network Modeling

Flux estimation (when applicable)

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 ReprogrammingGlycolysis / TCA Cycle FluxIsotope-Tracer Fate MappingCellular Energy MetabolismDrug Metabolism Mechanisms

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.