The Glycine N-Methyltransferase (GNMT) antibody is a research tool designed to detect and study the GNMT enzyme, a key regulator of methionine metabolism and DNA methylation. GNMT catalyzes the conversion of S-adenosylmethionine (SAMe) and glycine into sarcosine and S-adenosylhomocysteine (SAH), playing a critical role in maintaining the methylation potential of tissues . Its downregulation is associated with hepatocellular carcinoma (HCC) and hypermethioninemia due to disrupted methionine metabolism .
Bio-Techne’s MAB6526 antibody successfully demonstrated immunoprecipitation of recombinant GNMT from spiked cell lysates and detected a 37 kDa band in mouse liver lysates via Western blot . Prospec’s ANT-590 antibody is validated for ICC/IF, enabling subcellular localization studies .
A 2019 study revealed that the MYC oncogene directly represses GNMT transcription by binding to its core promoter, with MYC knockdown inducing GNMT expression in HCC cells . This interaction is critical in HCC pathogenesis, as GNMT downregulation correlates with tumor progression and poor prognosis .
GNMT antibodies are used to study therapeutic agents like penta-O-galloyl-beta-D-glucose (PGG), which suppresses MYC and restores GNMT activity in HCC models . This highlights GNMT’s potential as a biomarker for epigenetic therapies targeting methylation defects.
Diagnostic Development: GNMT antibodies could enable non-invasive detection of HCC through circulating protein analysis.
Therapeutic Targeting: Inhibiting MYC or modulating methionine metabolism may restore GNMT function in cancers.
Epigenetic Studies: GNMT’s role in balancing SAMe/SAH ratios makes it a focal point for understanding DNA methylation disorders .
Glycine N-methyltransferase (GNMT) is a cytoplasmic homotetramer enzyme that catalyzes the methylation of glycine using S-adenosylmethionine (AdoMet) to form N-methylglycine (sarcosine), with the concomitant production of S-adenosylhomocysteine (AdoHcy). It plays a critical role in regulating methyl group metabolism by controlling the ratio between S-adenosyl-L-methionine and S-adenosyl-L-homocysteine. GNMT is highly expressed in liver tissue, with expression also detected in pancreas and prostate tissues. Research indicates it functions as a potential tumor suppressor and is commonly downregulated in hepatocellular carcinoma .
GNMT antibodies come in several types with different characteristics:
| Antibody Type | Host Species | Examples | Key Features |
|---|---|---|---|
| Polyclonal | Rabbit, Sheep | ab203396, AF6526 | Recognize multiple epitopes, higher sensitivity, some batch variation |
| Monoclonal | Mouse | Clone 5D1 (NBP2-59452), Clone 691305 (MAB6526) | Single epitope recognition, higher specificity, better reproducibility |
The choice depends on experimental needs, considering species reactivity (human, mouse, rat, pig), application compatibility (WB, IHC, IF/ICC, ELISA), and detection requirements .
GNMT has a calculated molecular weight of approximately 32-33 kDa, with a 295 amino acid length in humans. In Western blot experiments, GNMT typically appears as a band at approximately 33-37 kDa depending on experimental conditions and the species being studied. This information is critical for proper identification and validation of the target protein when using GNMT antibodies .
Based on available validation data, the following techniques have been reliably used with GNMT antibodies:
| Technique | Typical Dilutions | Notes |
|---|---|---|
| Western Blot (WB) | 1:500-1:50,000 | Most widely validated; optimal for expression analysis |
| Immunohistochemistry (IHC) | 1:200 | Effective with FFPE tissues; good for localization studies |
| Immunofluorescence (IF/ICC) | 1:400-1:1,600 | Useful for subcellular localization in cell lines |
| ELISA | Varies by kit | Applicable for quantitative measurement |
The choice depends on your research question: WB for expression levels, IHC for tissue distribution, IF/ICC for subcellular localization, and ELISA for quantitative analysis .
Optimal GNMT detection requires tissue-specific preparation:
For Western Blot:
Liver tissue (high GNMT expression): Standard RIPA buffer with protease inhibitors
Pancreatic tissue: Specialized buffers with additional protease inhibitors due to high protease content
Cell lines: Complete lysis with RIPA or similar detergent-containing buffers
For IHC/IF:
Formalin fixation followed by paraffin embedding (FFPE) with appropriate antigen retrieval
For cultured cells, 4% paraformaldehyde fixation followed by 0.1-0.5% Triton X-100 permeabilization
To prevent degradation, process samples immediately or flash-freeze, maintain appropriate temperature, and include protease inhibitors in all buffers .
A comprehensive validation approach includes:
Positive controls: Liver tissue lysates where GNMT is highly expressed
Negative controls: GNMT knockdown/knockout samples or tissues with minimal expression
Blocking peptide competition: Signal elimination when antibody is pre-incubated with immunizing peptide
Multiple antibody comparison: Testing different antibodies targeting different GNMT epitopes
Correlation with mRNA expression: Comparing protein detection with GNMT mRNA levels
Western blot analysis: Confirming detection at the expected molecular weight (33-37 kDa)
Well-validated antibodies should show consistent results across these validation methods .
| Challenge | Possible Causes | Solutions |
|---|---|---|
| Non-specific bands | Cross-reactivity, degradation | Optimize antibody dilution (1:1000-1:5000), increase blocking time/concentration, use monoclonal antibodies |
| Weak/no signal | Low expression, poor extraction | Verify GNMT expression in sample, use liver as positive control, reduce antibody dilution, optimize antigen retrieval |
| Inconsistent results | Protocol variation, antibody degradation | Standardize protocols, include identical controls, consider switching to monoclonal antibodies |
| Species cross-reactivity issues | Epitope differences between species | Verify sequence homology, test species-validated antibodies, use antibodies against conserved regions |
| Background in IHC/IF | Inadequate blocking, non-specific binding | Increase blocking time, optimize antibody concentration, include additional wash steps |
Systematic troubleshooting based on careful controls can resolve most common issues .
For maintaining GNMT antibody functionality:
Long-term storage: -20°C to -70°C as recommended (12 months from receipt)
Short-term/working aliquots: 4°C for up to one month
Avoid repeated freeze-thaw cycles by creating small, single-use aliquots
Store in manufacturer's buffer (typically PBS with 0.02% sodium azide and 50% glycerol)
Prepare fresh working dilutions for each experiment
Document receipt date, lot number, and usage to track performance
Follow manufacturer-specific recommendations, as storage conditions may vary slightly between products .
Several factors can impact experimental reproducibility:
Antibody factors:
Lot-to-lot variation (especially with polyclonal antibodies)
Storage conditions and freeze-thaw cycles
Working dilution consistency
Sample factors:
Tissue heterogeneity and preparation methods
Protein degradation during storage/preparation
Variations in fixation times and protocols for IHC/IF
Protocol factors:
Inconsistent blocking conditions
Variation in incubation times and temperatures
Detection system sensitivity differences
To maximize reproducibility, standardize all protocols with detailed documentation, include appropriate controls in each experiment, and consider using monoclonal antibodies for critical studies .
GNMT antibodies enable several advanced approaches to investigate GNMT's tumor suppressor role:
Expression profiling:
Compare GNMT protein levels in HCC versus normal tissue using IHC or WB
Correlate expression with clinicopathological parameters and patient outcomes
Subcellular localization studies:
Track GNMT localization changes during hepatocarcinogenesis using IF/ICC
Monitor potential nuclear translocation under different conditions
Protein-protein interaction analysis:
Use co-immunoprecipitation with GNMT antibodies to identify cancer-specific interaction partners
Validate interactions through reciprocal co-IP and proximity ligation assays
Post-translational modification assessment:
Combine GNMT immunoprecipitation with mass spectrometry for PTM identification
Correlate modifications with functional changes in cancer progression
These approaches help establish GNMT's mechanistic role in liver cancer development and potential as a biomarker or therapeutic target .
The interaction between GNMT and folate metabolism (particularly 5-methyltetrahydrofolate which inhibits GNMT activity) can be studied using:
Co-immunoprecipitation and pull-down assays:
Use GNMT antibodies to immunoprecipitate protein complexes
Identify folate-related binding partners through Western blot or mass spectrometry
Protein activity assays:
Measure GNMT enzymatic activity with varying folate compound concentrations
Correlate activity with protein levels detected by GNMT antibodies
Cellular localization studies:
Track GNMT localization under folate-deficient or supplemented conditions
Co-localize with folate metabolism enzymes using dual immunofluorescence
Transgenic model validation:
Confirm GNMT expression/knockout in experimental models
Monitor folate metabolism markers and methylation status
These approaches help elucidate how GNMT and folate pathways interact to regulate methyl group metabolism .
Investigating GNMT post-translational modifications requires specialized approaches:
Sequential immunoprecipitation:
First IP: Use general GNMT antibodies to isolate total GNMT
Second analysis: Probe with PTM-specific antibodies (anti-phospho, anti-acetyl)
2D gel electrophoresis:
Separate GNMT isoforms based on charge (reflecting PTMs) and mass
Western blot with GNMT antibodies to identify modified forms
Mass spectrometry integration:
Immunoprecipitate GNMT using validated antibodies
Analyze by mass spectrometry to identify and map PTMs
Confirm findings using site-specific mutants
Physiological context analysis:
Study PTM changes in response to cellular stressors or disease states
Correlate modifications with GNMT enzymatic activity
These methods can reveal how PTMs regulate GNMT function in normal physiology and disease .
When working across multiple species, addressing antibody cross-reactivity requires:
Sequence alignment analysis:
Perform bioinformatic analysis of GNMT sequence homology across target species
Human GNMT shares 92% amino acid identity with mouse and rat GNMT
Select antibodies targeting highly conserved regions for multi-species detection
Epitope-specific validation:
Validate each antibody separately in each species of interest
Use positive controls (liver tissue) from each species
Confirm appropriate molecular weight, which may vary slightly between species
Multiple antibody approach:
Use antibodies targeting different epitopes
Concordant results across antibodies increase result reliability
This strategic approach ensures valid cross-species comparisons in evolutionary or animal model studies .
To investigate GNMT's role in methylation-dependent gene regulation:
Combined protein-epigenetic analysis:
Correlate GNMT protein levels (via antibody detection) with:
Global DNA methylation patterns
Gene-specific promoter methylation
Expression of methylation-sensitive genes
ChIP-based approaches:
Use antibodies against methylated DNA or methyl-binding proteins
Compare methylation patterns in models with varying GNMT expression
Intervention studies:
Manipulate GNMT levels through overexpression/knockdown
Monitor changes in DNA methylation and gene expression
Validate GNMT expression changes using validated antibodies
These approaches help establish mechanistic links between GNMT activity, methyl group metabolism, and epigenetic regulation .
Recent advances in single-cell technologies have enabled novel applications of GNMT antibodies:
Single-cell proteomics:
Mass cytometry (CyTOF) incorporation of metal-conjugated GNMT antibodies
Analysis of GNMT expression heterogeneity at single-cell resolution
Spatial transcriptomics integration:
Combining GNMT immunofluorescence with spatial transcriptomics
Correlating protein localization with gene expression patterns within tissue architecture
Multi-parameter imaging:
Multiplexed immunofluorescence including GNMT with other metabolic enzymes
Spatial relationship analysis between GNMT and interacting partners
These approaches reveal cell-to-cell variation in GNMT expression and its relationship to cellular metabolism and disease states .
When incorporating GNMT antibody data into machine learning algorithms:
Data standardization requirements:
Consistent staining protocols and imaging parameters
Standardized quantification methods for IHC/IF intensity
Normalization protocols for cross-study comparisons
Feature extraction considerations:
Subcellular localization patterns beyond simple expression levels
Contextual information (surrounding tissue architecture, co-expressed proteins)
Temporal dynamics when available
Validation framework:
Independent validation cohorts with standardized antibody protocols
Multi-antibody verification to confirm findings
Integration with orthogonal data types (genomics, transcriptomics)
Machine learning approaches can help identify complex patterns associating GNMT expression with disease progression or treatment response that might not be apparent through conventional analysis .
Integrative multi-omics approaches combining antibody-based techniques with genomics include:
Antibody-validated ChIP-seq:
Use GNMT antibodies for chromatin immunoprecipitation followed by sequencing
Identify potential DNA binding sites if GNMT has chromatin-associated roles
Integrated protein-expression analysis:
Correlate GNMT protein levels (antibody-detected) with:
RNA-seq transcriptional profiles
GNMT genetic variants (from genome sequencing)
Methylome patterns in the same samples
CRISPR screen validation:
Use GNMT antibodies to validate the effects of CRISPR-mediated genetic modifications
Confirm protein-level changes following genomic editing
This multi-modal approach provides complementary layers of evidence for GNMT's role in cellular processes and disease mechanisms .