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- Table of Contents
OPRM1 / Mu-type opioid receptor · Western blot design guide
Design a Western Blot for OPRM1
Source-linked OPRM1 Western blot protocol options, expected-band and isoform facts, troubleshooting for weak or shifted signal, and recommended anti-OPRM1 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
OPRM1 Western Blot Experimental Design Guide
Expected bands, source-linked protocol options, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before running
| Expected band | ~44.8 kDa | |
| Observed band | ~70 kDa | |
| Gel | 5–20% (catalog A00737-2) | |
| Positive control | Testis (IHC candidate; verify WB) | |
| Negative control | Adipose tissue (IHC candidate; verify WB) |
Important caveats
Reasons your observed band may differ from the expected size.
| PTM | Glycosylated + Phosphorylated | |
| Caveat | Modification-state controls | |
| Gene-set association | MSigDB C7 membership | |
| Isoform | 18 isoform(s) |
Section 1
Source-Linked OPRM1 Western Blot Protocol Options
The A00737-2 protocol combines labelled catalog values with standard starting conditions. Published comparisons retain their own sample, reagent and detection scope.
| Sample / lysate | human SH-SY5Y, human K562, human Jurkat, human U251, rat brain, rat heart, mouse brain, mouse heart (catalog A00737-2) |
| Gel % | 5–20% (catalog A00737-2) |
| Load | 30 ug; reducing conditions (catalog A00737-2) |
| Transfer | a nitrocellulose membrane at 150 mA for 50-90 minutes (catalog A00737-2) |
| Membrane | nitrocellulose membrane (catalog A00737-2) |
| Blocking | 5% non-fat milk/TBS for 1.5 hour at RT (catalog A00737-2) |
| Primary antibody | A00737-2 · 0.5 μg/mL (catalog A00737-2) |
| Primary incubation | overnight at 4°C (catalog A00737-2) |
| Secondary antibody | goat anti-rabbit IgG-HRP, 1:5000 (catalog A00737-2) |
| Secondary incubation | 1.5 hour at RT (catalog A00737-2) |
| Wash | TBS-0.1%Tween 3 times with 5 minutes each (catalog A00737-2) |
| Detection | ECL (catalog A00737-2) |
Section 2
What Is the Expected OPRM1 Western Blot Band Size?
OPRM1 is predicted at 44.8 kDa and observed near 70 kDa in antibody QC; the cause of the difference is not established.
| Band near 70 kDa | Empirical OPRM1 band; confirm identity with appropriate controls |
| Band near 44.8 kDa | Near the predicted mass of the 400-residue sequence |
| Diffuse band | Could reflect variable N-linked glycosylation; the listed sites alone do not establish a smear |
| Several bands at different positions | Could reflect OPRM1 isoforms; their migration differences are not established |
| Band near twice the monomer size | Could reflect an OPRM1 homooligomer if it remains intact during electrophoresis |
💡Expected OPRM1 appearanceOPRM1 has a predicted mass of 44.8 kDa, while antibody QC reports a band near 70 kDa in reducing lysates; verify its identity with ordinary band-identity controls because the cause of the difference is unproven.
| Predicted OPRM1 mass | 44.8 kDa for the supplied sequence; this is not its observed migration |
| N-linked glycosylation at Asn9 and Asn12 | May increase apparent mass if present; the size effect is not supplied |
| N-linked glycosylation at Asn33, Asn40 and Asn48 | May increase apparent mass if present; the size effect is not supplied |
| OPRM1 homooligomer formation | Could yield a higher band if an oligomer survives electrophoresis; no oligomer band is established |
| Splice isoforms 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 and 18 | May differ in size, but individual masses and resolvable band positions are not supplied |
| Situation | Likely cause | Next action |
|---|---|---|
| No band in lysate | OPRM1 is a multipass membrane protein that may be poorly recovered in the lysate | Check membrane-protein extraction and a positive-control lysate |
| Band higher than expected | N-linked glycosylation or an SDS-stable oligomer is possible; neither is established as the cause of the 70 kDa band | Compare glycosidase-treated samples and verify band identity with an independent antibody or OPRM1 loss control |
| Band lower than expected | An OPRM1 isoform or altered glycosylation is possible | Check antibody epitope coverage and verify the band with an OPRM1 loss control |
| Broad smear instead of sharp band | Variation in N-linked glycosylation is possible but not demonstrated | Compare glycosidase-treated and untreated samples and check band specificity |
| Multiple bands | OPRM1 has 18 listed isoforms, though distinct migration is not established | Check isoform coverage of the antibody and compare with an OPRM1 loss control |
| Weak or no signal | Recovery of this multipass membrane receptor may be low | Enrich the membrane fraction and check a positive-control lysate |
Experiment evidence
Western blot images showing OPRM1 band
A00737-2 · OPRM1
← swipe / scroll for more images →
Real WB data behind the band-size expectations in this section.
Sample controls for OPRM1 Western blot
🧪HPA-IHC candidate guidance (verify in WB): For positive controls for OPRM1 in Western blot, you can use testis tissue.
Positive control: Testis (IHC candidate; verify WB)
Negative control: Adipose tissue (IHC candidate; verify WB)
Loading controls: Run GAPDH, β-actin, and a total-protein stain alongside the samples.
⚠️Feasibility: As a multi-pass membrane protein, OPRM1 may be easier to detect in membrane-enriched lysate.
HPA tissue expression evidence for OPRM1
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 |
|---|---|---|---|---|
| Testis | elongated or late spermatids | 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 → |
| Adrenal gland | glandular cells | Not detected | Protein (IHC) | HPA → |
| Appendix | glandular cells | Not detected | Protein (IHC) | HPA → |
| Bone marrow | hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Breast | adipocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced OPRM1 Western Blot Tips
Deeper troubleshooting and optimisation questions for OPRM1, answered from its protein features.
How should OPRM1 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.
How can OPRM1 isoforms affect band interpretation?
Isoforms · UniProt lists 18 isoforms with several substantial sequence changes. Isoforms 12, 14, and 15 lack residues 1–100, while isoforms 16–18 have extensive changes beyond residue 97. Check whether the antibody epitope is retained in the isoforms you intend to detect before assigning bands.
Which glycosylation sites should I consider when assessing band shifts?
PTM · The listed N-linked sites are Asn9, Asn12, Asn33, Asn40, and Asn48 in UniProt canonical numbering. Compare untreated and enzymatically deglycosylated samples to assess whether glycosylation contributes to migration; the site annotations alone do not predict a visible shift.
UniProt lists phosphotyrosine 168, phosphoserines 365 and 377, and phosphothreonines 372 and 396. These are canonical sequence coordinates; antibody or paper numbering may differ. A phosphorylation annotation does not establish a detectable band shift, so avoid assigning a shifted band to phosphorylation without additional evidence.
UniProt lists phosphotyrosine 168, phosphoserines 365 and 377, and phosphothreonines 372 and 396. These are canonical sequence coordinates; antibody or paper numbering may differ. A phosphorylation annotation does not establish a detectable band shift, so avoid assigning a shifted band to phosphorylation without additional evidence.
Does this guide establish induction of OPRM1?
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 OPRM1?
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 A00737-2 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 I quantify OPRM1 across samples?
Quantitation · Define which OPRM1 isoforms the antibody can recognize and quantify the same assigned band or band set across samples. With 18 listed isoforms and five N-linked glycosylation sites, a single band's intensity need not represent every OPRM1 form.
Why might OPRM1 appear near 70 kDa instead of 44.8 kDa?
Interpretation · The predicted mass is 44.8 kDa, while the supplied observed band is about 70 kDa. OPRM1 has five N-linked glycosylation sites, alternative isoforms, and reported oligomerization. These features warrant investigation, but their presence alone does not establish the cause of the apparent mass difference.
UniProt reports OPRM1 homooligomers and heterooligomers with other GPCRs, including OPRD1 and OPRK1. This makes oligomerization a possibility when investigating higher bands, but it does not identify any particular Western blot band as an oligomer.
Check its apparent mass against the 44.8 kDa prediction and the supplied approximately 70 kDa observation, then check antibody epitope coverage across isoforms. Consider the listed glycosylation sites and oligomerization when planning follow-up experiments; none alone confirms the identity of an unexpected band.
UniProt reports OPRM1 homooligomers and heterooligomers with other GPCRs, including OPRD1 and OPRK1. This makes oligomerization a possibility when investigating higher bands, but it does not identify any particular Western blot band as an oligomer.
Check its apparent mass against the 44.8 kDa prediction and the supplied approximately 70 kDa observation, then check antibody epitope coverage across isoforms. Consider the listed glycosylation sites and oligomerization when planning follow-up experiments; none alone confirms the identity of an unexpected band.
Boster reagents
OPRM1 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-OPRM1 Antibody Picoband®
Cat # A00737-2
The catalog reports one anti-OPRM1 antibody for Western blot, A00737-2, with stated human, mouse, and rat reactivity. Its WB image shows a band near 70 kDa across the listed lysates, versus an expected 45 kDa; no orthogonal confirmation is supplied.
Which to pick: A00737-2 is the only listed option. Its WB image includes human cell, rat tissue, and mouse tissue lysates. Check whether the approximately 70 kDa band fits your assay before use, given the stated 45 kDa expected size.
Source: BosterBio OPRM1 gene-info card — filtered to Western-blot-capable antibodies; each card shows that product's actual WB validation figure.
References
- UniProt Consortium. UniProt entry P35372.
- Human Protein Atlas. OPRM1 tissue expression.
- PMC3137187 — target-verified WB comparison
- PMC6704399 — target-verified WB comparison
- PMC13609293 — target-verified WB comparison