Stable Isotope Research Applications

Stable Isotope Assays for Targeted Protein Half-Life

We quantify muscle protein synthesis, turnover, and half-life using deuterium oxide (D₂O) and amino acid tracer methods. Our assays deliver dynamic, reproducible endpoints that help researchers understand muscle remodeling and metabolic responses with regulatory-ready precision.

Trusted by Pharma and Biotech to Validate Mechanism of Action

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35+ Years exclusively in stable isotope tracer studies

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Experimental protocol designs and results delivered weeks faster than CROs
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GLP-compliant, CLIA-certified, 21 CFR Part 11 validated

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Consultative approach, with over 1,000+ studies guided from design to submission

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Understanding Targeted Protein Half-Life

Protein turnover reflects the balance between synthesis and degradation, and directly influences protein stability in vivo. Using D₂O as a tracer, deuterium becomes incorporated into amino acids during de novo synthesis and ultimately into newly formed proteins. As these proteins accumulate label over time, predictable isotopic patterns emerge that can be quantified by mass spectrometry.

By analyzing how mass isotopomer distributions evolve—such as M0 depletion or enrichment plateaus—researchers can derive fractional synthesis rates, turnover rate constants, and half-lives for proteins across tissues or targeted protein classes.

Endpoints & Readouts

Tracer & Analytical Approaches

Our assays provide:

  • Fractional synthesis rates (FSR)
  • Targeted protein half-lives
  • Turnover rate constants
  • Mass isotopomer distribution analysis (M0 depletion, enrichment curves)
  • Deuterium incorporation into amino acids
  • Labeling patterns in newly synthesized proteins
  • Mass spectrometry–based peptide isotopomer quantification

These measurements deliver mechanistic insight into protein remodeling and stability.

D₂O Metabolic Labeling for In Vivo Protein Turnover

Flexible for preclinical and clinical research.

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D₂O labeling enables pathway-independent incorporation of deuterium into amino acids and newly synthesized proteins. In preclinical studies, this includes small-animal dosing approaches such as oral or combined intraperitoneal (IP) + oral administration, as illustrated in standard rodent models.

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Amino Acid Label Incorporation

Deuterium entry into the precursor pool.

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As amino acids undergo de novo synthesis, multiple hydrogen positions can be replaced by deuterium, creating an enriched precursor pool for new protein synthesis. The number of incorporable positions varies (n), allowing sensitive isotopomer detection.

Mass Spectrometry of Newly Synthesized Proteins

Quantifying peptide isotopomers to model turnover.

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Newly synthesized proteins carry measurable deuterium signatures. Mass spectrometry quantifies these peptide isotopomers, enabling modeling of incorporation curves and derivation of protein synthesis rates and half-lives.

How Researchers Use Protein Half-Life Measurements

The following measurements offer a dynamic, pathway-independent view of protein turnover. Our D₂O-based assays support:

  • Characterization of targeted protein stability
  • Evaluation of turnover behavior across tissues
  • Longitudinal assessment of protein remodeling
  • Mechanistic understanding of protein lifespan

All Analyses Are Performed In Our Certified Laboratory Environment

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Trusted by Leaders in Metabolic Research

They’ve been very consistent… the sample analysis and data has always been timely and high quality.

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Dan Tardiff CAMP4

There are academic labs that do it as well, but they’re much harder to engage and contract with.

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Scott Turner Arda Therapeutics

I think they’re extremely organized and very on top of sample management. All the interactions that I’ve had with them have been great.

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Morganne A. Ultragenyx
Looking for Answers?

Frequently Asked Questions

Can D₂O labeling be applied to preclinical models?

Yes. The method is compatible with small animal studies and can support oral or combined dosing approaches.

How is protein half-life determined?

Half-lives are derived from isotopomer distribution modeling, including evaluation of M0 depletion or enrichment plateau behavior.

What analytical platform is used?

Mass spectrometry is used to quantify peptide isotopomers and model turnover kinetics.

Are your assays GLP/CLIA compliant?

Yes. All analyses are performed in a GLP-compliant, CLIA-certified laboratory under 21 CFR Part 11–validated workflows.

Contact Us

Measure Targeted Protein Half-Life With Confidence

Our D₂O-based tracer methods provide reproducible insight into targeted protein turnover and stability. Let’s design the right protocol for your study.
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Metabolic Solutions, LLC.
460 Amherst St., Nashua,
NH 03063, USA

Hours of Operation
Monday – Friday
7:30 am – 6:00 pm EST 

Contact us

Metabolic Solutions, LLC.
460 Amherst St., Nashua, NH 03063, USA

(603) 598-6960

(603) 598-6973

Breath Tests: support@metsol.com

Research: info@metsol.com

Hours of Operation
Monday – Friday
7:30 am – 6:00 pm EST

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