Methionine Cycle Analysis Service
Creative Proteomics provides high-precision methionine cycle analysis using advanced LC-MS/MS technology, enabling accurate quantification of key metabolites. We help researchers investigate metabolic pathways, assess biochemical changes, and optimize experimental outcomes in fields like biotechnology, nutrition, and environmental science. Our service ensures reliable data with strict quality control, fast turnaround, and customizable analysis to meet diverse research needs.
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- What We Provide
- Advantages
- Technology Platform
- Sample Requirements
- FAQ
- Publications
What is Methionine Cycle?
The methionine cycle is a fundamental biochemical pathway essential for methyl group transfer, amino acid metabolism, and cellular redox balance. This cycle involves the interconversion of methionine (Met), S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), and homocysteine (HCY). Dysregulation of this pathway is associated with cardiovascular diseases, neurodegenerative disorders, cancer, and developmental defects. At Creative Proteomics, we provide methionine cycle analysis services to quantify key metabolites within this cycle, empowering researchers to investigate its role in health and disease.
Methionine metabolism in health and cancer: a nexus of diet and precision medicine (Sanderson et al., 2019).
Methionine Cycle Analysis Service Offered by Creative Proteomics
- Targeted Metabolite Quantification: Absolute quantification of 9 core metabolites (e.g., methionine, homocysteine, SAM, SAH, glutathione) using isotope-labeled internal standards. Ideal for pathway activity profiling in cell lines, animal models, or plant systems.
- Custom Metabolite Panel Development: Tailored assay design to detect novel intermediates, derivatives, or species-specific metabolites (e.g., methylated compounds in extremophiles).
- Dynamic Metabolic Flux Analysis: Stable isotope tracing (¹³C/²H-labeled methionine) to map real-time metabolic flux in in vitro or in vivo systems. Applications include drug response studies or nutrient utilization analysis.
- Stress Response & Toxicity Studies: Quantify redox balance (GSH/GSSG ratio) and methylation capacity (SAM/SAH) in models exposed to oxidative stress, heavy metals, or metabolic inhibitors.
- Biomarker Discovery & Disease Correlation Studies – Identify disease-associated metabolic alterations in clinical and preclinical models.
Detectable Methionine Cycle Metabolites
| Metabolite | Role in Cycle | Detection Limit (LOD) |
|---|---|---|
| Methionine (Met) | Methyl donor precursor; critical for protein synthesis and methylation reactions. | 0.5 nM |
| Homocysteine (HCY) | Key junction metabolite in transsulfuration and remethylation; linked to cardiovascular risk. | 0.2 nM |
| S-Adenosylmethionine (SAM) | Universal methyl donor; regulates epigenetic modifications (DNA/RNA/protein methylation). | 0.1 nM |
| S-Adenosylhomocysteine (SAH) | SAM hydrolysis product; competitive inhibitor of methyltransferases. | 0.1 nM |
| Cysteine (Cys) | Transsulfuration pathway intermediate; precursor for glutathione synthesis. | 0.3 nM |
| Glutathione (GSH/GSSG) | Central redox balance regulator; reflects cellular oxidative stress. | 0.4 nM |
| Choline | Methyl metabolism cofactor; supports phospholipid synthesis. | 0.5 nM |
| Betaine | Facilitates HCY remethylation via betaine-homocysteine methyltransferase (BHMT). | 0.6 nM |
| 5-Methyltetrahydrofolate (5-MTHF) | Integrates folate cycle with methionine metabolism; provides methyl groups. | 0.3 nM |
| Cystathionine | Transsulfuration intermediate; generated by cystathionine beta-synthase (CBS). | 0.4 nM |
| Adenosine | Byproduct of SAM metabolism; modulates cellular signaling pathways. | 0.5 nM |
| Dimethylglycine (DMG) | Betaine metabolism derivative; participates in methyl group recycling. | 0.7 nM |
| 5,10-Methylenetetrahydrofolate (5,10-CH₂-THF) | Methylene group donor; essential for thymidylate synthesis. | 0.3 nM |
| 10-Formyltetrahydrofolate (10-FTHF) | Formyl group donor; critical for purine biosynthesis. | 0.3 nM |
| Methionine Sulfoxide | Oxidized methionine derivative; biomarker of oxidative stress. | 0.8 nM |
Advantages of Methionine Cycle Assay
- High Sensitivity & Accuracy – Detects metabolites at pM to nM levels with CV < 10% using LC-MS/MS.
- Comprehensive Metabolite Coverage – Measures key methionine cycle metabolites and related pathways, including SAM, SAH, and homocysteine.
- Advanced Instrumentation – AB SCIEX QTRAP 6500+, Agilent 6495C, for precise and reliable analysis.
- High Reproducibility – Ensures RSD < 15% with strict quality control and internal standards.
- Wide Sample Compatibility – Supports serum, plasma, urine, CSF, tissues, and cell culture media with minimal volume requirements.
- Fast Turnaround Time – Delivers results within 6–8 weeks, with priority processing available.
- Customizable & Data-Driven – Provides custom metabolite panels, statistical analysis, and pathway interpretation.
Technology Platforms for Methionine Cycle Analysis Service
- HPLC System: Agilent 1290 UHPLC coupled with BEH C18 column (1.7 µm, 2.1 × 100 mm).
- Mass Spectrometer: Agilent 6495C Triple Quadrupole mass spectrometer equipped with an electrospray ionization (ESI) source (MRM mode).
- Chromatography: Gradient elution using ammonium acetate buffer/methanol (30°C column temperature).
- Data Processing: Process data using MassHunter software, including peak area calculation, standard curve fitting, and quantitation.
Agilent 1290 UHPLC System (Figure from Agilent)
Agilent 6495C Triple Quadrupole (Figure from Agilent)
Sample Requirements for Methionine Cycle Analysis Service
| Sample Type | Required Volume/Amount | Collection Method | Storage Conditions | Additional Notes |
|---|---|---|---|---|
| Serum | ≥ 100 µL | Collect in a serum separation tube, allow clotting, centrifuge at 3000 × g for 10 min | Store at -80°C, avoid freeze-thaw cycles | Aliquot to minimize degradation |
| Plasma | ≥ 100 µL | Collect in EDTA/heparin tube, centrifuge at 3000 × g for 10 min | Store at -80°C, avoid freeze-thaw cycles | Specify anticoagulant used |
| Urine | ≥ 500 µL | Collect midstream urine in a sterile container | Store at -80°C, no preservatives | Avoid bacterial contamination |
| Cell Culture Media | ≥ 1 mL | Collect from conditioned media, centrifuge to remove debris | Store at -80°C, filter if necessary | Specify culture conditions |
| Tissue Samples | ≥ 50 mg | Flash-freeze immediately in liquid nitrogen | Store at -80°C, avoid repeated freeze-thaw | Provide sample weight and species |
| Cerebrospinal Fluid (CSF) | ≥ 200 µL | Collect via lumbar puncture in a sterile tube | Store at -80°C, avoid contamination | Handle with extreme care |
| Whole Blood | ≥ 200 µL | Collect in EDTA/heparin tube | Store at -80°C, mix gently to prevent clotting | Avoid hemolysis |
| Feces | ≥ 100 mg | Collect fresh sample, freeze immediately | Store at -80°C, avoid repeated freeze-thaw | No preservatives |
| Saliva | ≥ 500 µL | Collect in sterile tube, avoid eating/drinking before collection | Store at -80°C | No preservatives |
Applications of Methionine Cycle Assay Service
Metabolic Research
Investigate methionine metabolism and its role in methylation, redox balance, and amino acid synthesis.
Pharmaceutical & Drug Development
Assess the impact of compounds on methionine cycle activity, enzyme function, and metabolic flux.
Nutritional & Dietary Studies
Analyze the effects of dietary methionine levels, methyl donors, and metabolic interventions on cellular metabolism.
Microbial & Industrial Biotechnology
Explore methionine metabolism in microorganisms for fermentation, amino acid production, and metabolic engineering.
Environmental & Toxicology Studies
Evaluate how external stressors, pollutants, and toxins influence sulfur and methyl metabolism.
Agricultural & Plant Science
Study methionine metabolism in plants for crop improvement, stress resistance, and nutrient optimization.
FAQ of Methionine Cycle Analysis Service
How do you ensure data accuracy in low-concentration metabolites like SAM and SAH?
Our HPLC-MS/MS platform employs stable isotope-labeled internal standards (e.g., d8-methionine, ¹³C-SAM) to correct for matrix effects and ion suppression. For SAM and SAH, we achieve 0.1 nM LOD with <8% coefficient of variation (CV) across replicates. Pre-analytical protocols include N-ethylmaleimide (NEM) stabilization to prevent thiol oxidation, ensuring >95% recovery of labile metabolites like homocysteine.
Can I integrate methionine cycle data with other omics datasets (e.g., transcriptomics or proteomics)?
Yes. We provide multi-omics integration support, including:
- Pathway mapping: Correlate SAM/SAH ratios with DNA methylation or histone modification data.
- Custom bioinformatics: Merge metabolomic data with RNA-seq or proteomic results using tools like MetaboAnalyst or KEGG Mapper.
- Dynamic flux modeling: Combine isotope tracing data with kinetic models (e.g., COPASI) to predict pathway bottlenecks.
What is the optimal experimental design for isotope tracing (¹³C/²H-methionine) studies?
Key considerations include:
- Labeling duration: 24–48 hours for mammalian cell cultures to achieve isotopic steady state.
- Sampling timepoints: Collect at 0, 6, 12, 24 hours to capture flux dynamics in SAM synthesis and transsulfuration.
- Controls: Use unlabeled methionine controls to correct for natural isotope abundance. We provide free experimental design templates and QC spike-in protocols for tracer studies.
How do you handle samples prone to metabolite degradation (e.g., tissues with high protease activity)?
For sensitive tissues (e.g., liver or tumor biopsies):
- Rapid processing: Flash-freeze in liquid nitrogen within 5 minutes of excision.
- Stabilization buffers: Use pre-chilled PBS with 10 mM NEM and protease inhibitors.
- Homogenization: Cryogenic grinding under argon atmosphere to minimize oxidation. We validate recovery rates for each tissue type—contact us for tissue-specific SOPs.
Can you analyze methionine cycle intermediates in microbial or plant systems?
Absolutely. Our workflows are optimized for:
- Microbial cultures: Methionine auxotrophs (e.g., E. coli mutants) with detection of cystathionine (0.4 nM LOD) and 5-MTHF.
- Plant tissues: Quantify betaine and choline in drought-stressed models, with protocols for lignin-rich matrix removal. Species-specific calibration curves are included in custom panels.
What validation is provided for novel biomarkers identified in my study?
For custom biomarkers (e.g., dimethylglycine or methionine sulfoxide):
- Method validation: Linearity (R² > 0.99), precision (intra-day CV<10%), and spike-recovery (85–115%).
- Cross-laboratory verification: Partner labs replicate a subset of samples using orthogonal methods (e.g., GC-MS or enzymatic assays).
- Data packages: Raw MRM chromatograms, QC reports, and MIAME-compliant metadata.
How does your service support drug development studies targeting methionine metabolism?
We specialize in:
- Inhibitor screening: Dose-response curves for methyltransferase inhibitors (e.g., SAM-competitive compounds).
- Toxicity profiling: Monitor glutathione depletion (GSH/GSSG ratio) and homocysteine accumulation in hepatocyte models.
- PD/PK integration: Correlate drug exposure levels with methionine cycle metabolite shifts over time.
Learn about other Q&A.
Methionine Cycle Analysis Service Case Study
Publications
Here are some of the metabolomics-related papers published by our clients:
- A non-probiotic fermented soy product reduces total and ldl cholesterol: A randomized controlled crossover trial. 2021. https://doi.org/10.3390/nu13020535
- Resting natural killer cell homeostasis relies on tryptophan/NAD+ metabolism and HIF‐1α. 2023. https://doi.org/10.15252/embr.202256156
- Enhance trial: effects of NAD3® on hallmarks of aging and clinical endpoints of health in middle aged adults: a subset analysis focused on blood cell NAD+ concentrations and lipid metabolism. 2022. https://doi.org/10.3390/physiologia2010002
- Dimethyl fumarate treatment restrains the antioxidative capacity of T cells to control autoimmunity. 2021. https://doi.org/10.1093/brain/awab307
- Function and regulation of a steroidogenic CYP450 enzyme in the mitochondrion of Toxoplasma gondii. 2023. https://doi.org/10.1371/journal.ppat.1011566
References
- Sanderson, Sydney M., et al. "Methionine metabolism in health and cancer: a nexus of diet and precision medicine." Nature Reviews Cancer 19.11 (2019): 625-637. https://doi.org/10.1038/s41568-019-0187-8
- Guiraud, Seu Ping, et al. "High-throughput and simultaneous quantitative analysis of homocysteine–methionine cycle metabolites and co-factors in blood plasma and cerebrospinal fluid by isotope dilution LC–MS/MS." Analytical and bioanalytical chemistry 409 (2017): 295-305. http://dx.doi.org/10.1007/s00216-016-0003-1
