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- Table of Contents
MTAP / S-methyl-5'-thioadenosine phosphorylase · Western blot design guide
Design a Western Blot for MTAP
Real validated MTAP Western blot protocols, expected-band and isoform facts, troubleshooting for weak or shifted signal, and recommended anti-MTAP WB antibodies. Everything you need to plan the experiment before you commit precious samples.
Evidence assembled September 2026 · For research use; verify linked source records and product datasheet before use
MTAP Western Blot Experimental Design Guide
Expected bands, validated protocols, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before running
| Expected band | ~31.2 kDa | |
| Gel | 12–15% (standard starting point) | |
| Positive control | Breast (IHC candidate; verify WB) +4 more | |
| Negative control | Adipose tissue (IHC candidate; verify WB) |
Important caveats
Reasons your observed band may differ from the expected size.
| PTM | Acetylated | |
| Caveat | Modification-state controls | |
| Gene-set association | MSigDB C7 membership | |
| Isoform | 7 isoform(s) |
Section 1
Real Curated MTAP Western Blot Protocols
The M05448 protocol combines labelled catalog values with standard starting conditions. Published comparisons retain their own sample, reagent and detection scope.
| Sample / lysate | (1) 293T cell lysate; (2) NIH/3T3 cell lysate (catalog M05448) |
| Gel % | 12–15% (standard starting point) |
| Load | 20–30 µg total protein per lane; optimize for abundance (standard starting point) |
| Transfer | Standard semi-dry transfer; verify efficiency (standard starting point) |
| Membrane | 0.45 µm PVDF (standard starting point) |
| Blocking | 5% milk or 5% BSA in TBST (standard starting point) |
| Primary antibody | M05448; use the WB datasheet starting dilution (standard starting point) |
| Primary incubation | Overnight at 4 °C (standard starting point) |
| Secondary antibody | Species-matched HRP conjugate at validated dilution (standard starting point) |
| Secondary incubation | 1 h at room temperature (standard starting point) |
| Wash | 3 × 5 min in TBST (standard starting point) |
| Detection | ECL; bracket exposures to avoid saturation (standard starting point) |
Section 2
What Is the Expected MTAP Western Blot Band Size?
MTAP has a predicted mass of 31.2 kDa; isoforms may affect migration, but no empirical band size or distinct isoform pattern is established.
| Band near 31.2 kDa | Consistent with the predicted MTAP mass; identity requires confirmation |
| Several discrete bands | Could reflect MTAP isoforms if their migration differs; band identities are unverified |
| Band in a cytoplasmic fraction | Consistent with the reported cytoplasmic location of MTAP |
| Band in a nuclear fraction | Consistent with the reported nuclear location of MTAP |
💡Expected MTAP appearanceUniProt predicts MTAP at 31.2 kDa, but no empirical band size or resolvable isoform pattern is supplied; confirm any candidate band with an MTAP-specific identity control.
| Predicted MTAP mass | 31.2 kDa is the sequence-based reference, not a measured band |
| Isoform 1 | Its migration relative to the other named isoforms is unknown |
| Isoforms 2, 3, and 4 | Their relative sizes and migration are not supplied |
| Isoforms 5, 6, and 7 | Their relative sizes and migration are not supplied |
| Situation | Likely cause | Next action |
|---|---|---|
| No band in lysate | MTAP may be below detection in the tested lysate | Check loading and antibody performance with an MTAP-positive lysate |
| Band higher than expected | Band identity or migration is unverified; MTAP forms homotrimers, but their survival on the blot is unproven | Check sample denaturation and confirm the band with MTAP depletion |
| Band lower than expected | An MTAP isoform is possible, but isoform sizes are not supplied | Confirm the band with MTAP depletion or an independent antibody |
| Multiple bands | Seven MTAP isoforms are listed, but distinct migration is unproven | Use MTAP depletion to identify specific bands |
| Weak or no signal | MTAP may be below the assay's detection limit | Check loading and compare with an MTAP-positive lysate |
Experiment evidence
Western blot images showing MTAP band
M05448 · MTAP
M05448 · MTAP
A05448-2 · MTAP
← swipe / scroll for more images →
Real WB data behind the band-size expectations in this section.
Sample controls for MTAP Western blot
🧪HPA-IHC candidate guidance (verify in WB): For positive controls for MTAP in Western blot, you can use breast tissue, which HPA scores High.
Positive control: Breast (IHC candidate; verify WB)
Negative control: Adipose tissue (IHC candidate; verify WB)
Loading controls: Run GAPDH, β-actin, and a total-protein stain such as Ponceau alongside.
⚠️Feasibility: HPA reports no MTAP detection in adipose tissue, making a tissue negative control feasible.
HPA tissue expression evidence for MTAP
Comprehensive Human Protein Atlas IHC scoring per tissue. Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Higher expression tissues · candidate positive controls from IHC
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Breast | glandular cells | High | Protein (IHC) | HPA → |
| Bronchus | respiratory epithelial cells | High | Protein (IHC) | HPA → |
| Cervix | squamous epithelial cells | High | Protein (IHC) | HPA → |
| Epididymis | glandular cells | High | Protein (IHC) | HPA → |
| Gallbladder | glandular cells | High | Protein (IHC) | HPA → |
Lower expression tissues · IHC evidence, not confirmed WB-negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | adipocytes | Not detected | Protein (IHC) | HPA → |
| Cerebellum | cells in granular layer | Not detected | Protein (IHC) | HPA → |
| Cerebral cortex | endothelial cells | Not detected | Protein (IHC) | HPA → |
| Liver | cholangiocytes | Not detected | Protein (IHC) | HPA → |
| Parathyroid gland | glandular cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced MTAP Western Blot Tips
Deeper troubleshooting and optimisation questions for MTAP, answered from its protein features.
How should MTAP band migration be interpreted?
Band shift · Use the separately labelled calculated mass and catalog-observed evidence above. A sequence annotation does not establish an observed migration shift. Verify target identity with orthogonal controls.
Which MTAP isoforms could produce different bands?
Isoforms · UniProt lists seven isoforms. Isoforms 2–4 replace residues 272–283; isoforms 5–6 replace 231–283; isoform 7 replaces 232–283. Their altered C-terminal sequences may affect apparent bands, but the features do not establish which isoforms are expressed in your sample.
Check whether the antibody’s stated epitope overlaps the alternative sequences at residues 231–283. Recognition of isoforms 2–7 may differ if it does. An epitope outside those regions avoids this particular sequence difference, though binding still needs experimental validation.
Decide whether the measurement represents one band or all detected MTAP forms, and report that choice. Seven isoforms are listed, with several C-terminal sequence changes; the supplied features do not establish that an antibody detects each form equally.
Check whether the antibody’s stated epitope overlaps the alternative sequences at residues 231–283. Recognition of isoforms 2–7 may differ if it does. An epitope outside those regions avoids this particular sequence difference, though binding still needs experimental validation.
Decide whether the measurement represents one band or all detected MTAP forms, and report that choice. Seven isoforms are listed, with several C-terminal sequence changes; the supplied features do not establish that an antibody detects each form equally.
Could acetylation explain an MTAP band shift?
PTM · UniProt lists N6-acetyllysine at position 51, using UniProt sequence numbering. That modification alone does not demonstrate a visible shift. Keep the numbering convention explicit when comparing antibody or paper descriptions.
Does this guide establish induction of MTAP?
Induction · No general induction response is established by this guide. A pathway or gene-set association is not evidence of induction in a particular specimen. Verify the relevant treatment and control in a target-specific experiment.
How should transfer be checked for MTAP?
Transfer · Standard workflow guidance: verify transfer efficiency for the intended target size before interpreting a weak signal. Use total-protein assessment and optimize transfer for the membrane, gel and apparatus; the labelled catalog values take precedence.
How should blocking be optimized?
Blocking · Standard workflow guidance: follow the M05448 datasheet where specified. Otherwise compare 5% milk or 5% BSA in TBST; for a phospho-specific assay start with BSA. Optimize background and specific signal with matched controls.
How should MTAP be quantified?
Quantitation · Standard workflow guidance: quantify only a validated target band within the linear exposure range. Use consistent sample preparation and loading, retain biological replicates, and avoid interpreting saturation or loading differences as regulation.
Should MTAP migrate exactly at its predicted 31.2 kDa?
Interpretation · 31.2 kDa is the predicted mass of the 283-residue canonical sequence. No observed band position is supplied, so these features cannot establish an expected shift or explain a difference from 31.2 kDa.
UniProt describes MTAP as a homotrimer. That makes oligomerization relevant when investigating a higher band, but these features do not show that a trimer survives the blot conditions or identify any observed band.
UniProt lists MTAP in the cytoplasm and nucleus. A signal in either fraction is consistent with those locations. Compare fraction quality and band identity before interpreting different band intensities as a change in MTAP abundance.
UniProt describes MTAP as a homotrimer. That makes oligomerization relevant when investigating a higher band, but these features do not show that a trimer survives the blot conditions or identify any observed band.
UniProt lists MTAP in the cytoplasm and nucleus. A signal in either fraction is consistent with those locations. Compare fraction quality and band identity before interpreting different band intensities as a change in MTAP abundance.
Boster reagents
MTAP Western Blot Antibodies
Catalog antibodies with Western blot application and product-specific WB images. Evaluate suitability with the reported sample, controls and experimental conditions.
Real WB data
Anti-MTAP Rabbit Monoclonal Antibody
Cat # M05448
Real WB data
Anti-MTAP Antibody Picoband®
Cat # A05448-2
The catalog reports two anti-MTAP antibodies with Western blot images. M05448 is shown with 293T and NIH/3T3 lysates; A05448-2 is shown with HeLa, 293T, Raji, PC-12, and RAW264.7 lysates, with a reported band near 31 kDa. No publication evidence was supplied.
Which to pick: Both list human, mouse, and rat reactivity. Choose A05448-2 if you want an image that includes rat PC-12 lysate or detailed blot conditions; M05448 has an image using 293T and NIH/3T3 lysates. These examples do not establish performance in every sample.
Source: BosterBio MTAP gene-info card — filtered to Western-blot-capable antibodies; each card shows that product's actual WB validation figure.
References
- UniProt Consortium. UniProt entry Q13126.
- Human Protein Atlas. MTAP tissue expression.
- PMC11970323 — target-verified WB comparison
- PMC10241944 — target-verified WB comparison
- PMC8602418 — target-verified WB comparison