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MASP2 · Western blot design guide
Design a Western Blot for MASP2
Real validated MASP2 Western blot protocols, expected-band and isoform facts, troubleshooting for weak or shifted signal, and recommended anti-MASP2 WB antibodies. Everything you need to plan the experiment before you commit precious samples.
Last reviewed: May 2026 · Scientific review: Boster Bio technical team
MASP2 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 | ~75.7 kDa | |
| Observed band | ~76 kDa | |
| Gel | 10–12% | |
| Positive control | Adipose tissue+4 more · see all | |
| Negative control | Adipose tissue+4 more · see all |
Important caveats
Reasons your observed band may differ from the expected size.
| PTM | Cleaved + Disulfide-linked | |
| Caveat | Autocatalytic cleavage | |
| Regulation | Coagulation | |
| Isoform | 2 isoform(s) |
Section 1
Real Curated MASP2 Western Blot Protocols
Literature-validated Western blot parameters for MASP2 — gel percentage, transfer, blocking, antibody incubation and detection, extracted from published methods.
| Sample / lysate | human HepG2 , Lane 2: human Hela , Lane 3: human Caco-2 . After Electrophoresis, proteins were transferred to a Nitrocellulose membrane at 150mA for 50-90 minutes. Blocked the membrane with 5% Non-fat Milk/ TBS for 1.5 hour at RT. The membrane was incubated with rabbit anti-MASP2 antigen affinity purified polyclonal antibody (Catalog # A02323-1) at 0.5 μg/mL overnight at 4°C, then washed with TBS-0.1%Tween 3 times with 5 minutes each and probed with a goat anti-rabbit IgG-HRP secondary antibody at a dilution of 1:5000 for 1.5 hour at RT. The signal is developed using an Enhanced Chemiluminescent detection (ECL) kit (Catalog # EK1002) with Tanon 5200 system. A specific band was detected for MASP2 at approximately 76KD. The expected band size for MASP2 is at 76KD |
| Gel % | 10–12% |
| Load | 50ug |
| Transfer | nitrocellulose membrane, 150 mA, 50–90 min |
| Membrane | nitrocellulose |
| Blocking | 5% non-fat milk / TBS, 1.5 h RT |
| Primary antibody | 0.5 µg/mL |
| Primary incubation | overnight at 4 °C |
| Secondary antibody | goat anti-rabbit IgG-HRP, 1:5000 |
| Wash | TBS-0.1% Tween, 3 × 5 min |
| Detection | ECL |
| Exposure / imaging | Tanon 5200 |
| Observed band | 76 kDa |
Section 2
What Is the Expected MASP2 Western Blot Band Size?
MASP2's 75.7 kDa predicted mass matches its observed ~76 kDa band, since it lacks glycosylation despite forming a disulfide-linked homodimer and undergoing autocatalytic activation cleavage.
| Single band near 75-76 kDa under reducing conditions | Full-length monomeric MASP2 after signal peptide removal, matching the predicted mass since there is no glycosylation load |
| Band near ~150 kDa when reduction is incomplete | The disulfide-linked homodimer stays intact when boiling or reducing agent is insufficient to break the interchain bond |
| Extra band closely spaced to the main ~76 kDa band | Isoform 1 and isoform 2 arising from alternative splicing can resolve as distinct, similarly sized species |
| Smaller bands appearing below the main ~76 kDa band | Autocatalytic cleavage during zymogen activation splits MASP2 into disulfide-linked heavy and light chain fragments |
| Little or no band in whole-cell lysate | MASP2 is a secreted protein, so most of it is exported into extracellular fluid or serum rather than retained intracellularly |
💡Expected MASP2 appearanceMASP2 typically runs as a single band at approximately 76 kDa under reducing SDS-PAGE, closely matching its 75.7 kDa predicted mass since it carries no glycosylation.
| Predicted mass from UniProt (75.7 kDa, 686 aa) | sets the baseline monomer size under reducing conditions, consistent with the observed ~76 kDa band |
| Signal peptide cleavage (residues 1-15) | removes the N-terminal signal sequence in the secreted mature protein, so mature MASP2 runs at or slightly below the full-length translated mass |
| Disulfide-linked homodimer formation | under non-reducing or incompletely reduced conditions the two ~76 kDa subunits stay linked, shifting the apparent band toward roughly double the monomer mass |
| Alternative splicing (isoforms 1 and 2) | can generate an additional band relative to the canonical monomer, though relative isoform sizes are not specified |
| Situation | Likely cause | Next action |
|---|---|---|
| No band in lysate | MASP2 is secreted and largely exported into extracellular fluid or serum rather than retained in the cell | probe conditioned media, serum, or plasma, or concentrate the secreted fraction instead of relying on whole-cell lysate alone |
| Band higher than expected | incomplete reduction leaves the disulfide-linked homodimer intact near double the monomer mass | increase reducing agent concentration and boiling time before loading to fully separate the homodimer |
| Fragments below expected size | autocatalytic serine protease cleavage during zymogen activation generates disulfide-linked heavy and light chain fragments | use fresh, protease-inhibited and calcium-chelated sample prep to limit activation-associated cleavage before loading |
| Multiple bands | co-migration of isoform 1 and isoform 2, or a mix of uncleaved zymogen and activated cleavage products | compare band pattern against zymogen versus activated controls and check epitope location relative to the cleavage site |
| Weak or no signal | only a small fraction of secreted MASP2 is retained in a standard whole-cell lysate preparation | load higher total protein or switch to serum or plasma samples enriched in the secreted pool |
| Band lower than expected | loss of the disulfide-linked chain pairing after activation cleavage can shift signal toward a smaller fragment | run non-reducing alongside reducing lanes to distinguish intact zymogen from cleaved activation products |
Experiment evidence
Western blot images showing MASP2 band
A02323-1 · MASP2
← swipe / scroll for more images →
Real WB data behind the band-size expectations in this section.
Sample controls for MASP2 Western blot
🧪For positive controls for MASP2 in Western blot, you can use human serum or plasma, since MASP2 is a secreted circulating protease and the supplied HPA tissue panel shows no reliable positive tissue signal to draw a lysate control from.
Positive control: Human serum/plasma
Negative control: Adipose tissue (Not detected)
Loading controls: Run GAPDH and β-actin antibody blots alongside a total-protein stain (stain-free gel, Ponceau S, or REVERT) to confirm equal loading and transfer.
⚠️Feasibility: Because MASP2 is secreted rather than retained intracellularly, whole-cell tissue lysates give weak or absent signal even in Not-detected-negative comparisons, so positive controls should come from serum/plasma or conditioned medium rather than the sparse HPA tissue panel.
HPA tissue expression evidence for MASP2
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.
Positive expression · recommended positive 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 → |
Undetected expression · recommended 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 MASP2 Western Blot Tips
Deeper troubleshooting and optimisation questions for MASP2, answered from its protein features.
Why does the MASP2 band appear near 76 kDa?
Predicted mass is 75.7 kDa after removal of the 1-15 signal peptide, closely matching the ~76 kDa observed band. Minor shifts can arise from the 12 disulfide bonds altering SDS-PAGE mobility, so denaturing, reducing conditions give the most accurate size estimate for full-length MASP2.
Does MASP2 alternative splicing produce extra bands?
MASP2 has two annotated isoforms arising from alternative splicing. The shorter isoform lacks much of the serine protease region and migrates well below the ~76 kDa full-length band. Confirm which isoform region your antibody targets before interpreting lower-molecular-weight signals as degradation.
What causes lower-MW MASP2 fragments after activation?
MASP2 undergoes autocatalytic cleavage into disulfide-linked A and B chains when the lectin complement pathway is activated on pathogen surfaces. Samples with active complement signaling can show additional bands below full-length MASP2 corresponding to these cleavage fragments, particularly under reducing conditions.
Reducing or non-reducing gels for MASP2 detection?
MASP2 forms a disulfide-linked homodimer stabilized by 12 disulfide bonds. Non-reducing gels preserve the dimer and interchain links, shifting bands to a higher apparent MW; reducing conditions break these bonds and resolve the expected ~76 kDa monomer for accurate sizing.
What transfer method to use for MASP2 Western blot?
Use wet tank transfer given MASP2's disulfide-linked homodimer and 12 intrachain disulfide bonds, which can slow transfer of larger, compact complexes. Extend transfer time or reduce current for complete protein transfer, especially when non-reducing conditions are used to preserve the dimer.
How should MASP2 levels be normalized on blots?
Since MASP2 is a secreted plasma protein rather than an intracellular housekeeping-normalized protein, use total protein stain such as Ponceau S rather than GAPDH or actin. This avoids inaccurate normalization when comparing serum or plasma samples across conditions.
Could calcium-dependent complexes cause unexpected bands?
MASP2 binds MBL2 and FCN2 in a calcium-dependent manner. If EDTA or EGTA is omitted from sample buffers, these complexes may remain intact and appear as higher-molecular-weight bands. Include a calcium chelator during lysis to detect MASP2 independent of its binding partners.
Boster reagents
Best MASP2 Western Blot Antibodies
BosterBio's MASP2 antibodies are among the best-performing WB antibodies on the market — well cited, thoroughly validated, and orthogonally cross-validated against negative tissues and complementary methods.
Real WB data
Anti-MASP2 Antibody Picoband®
Cat # A02323-1
Our recommended anti-MASP2 antibody is a best-performing, extensively cited reagent, rigorously validated by western blot and cross-checked against negative tissue and complementary detection methods, giving confident, reproducible results for reliable MASP2 detection in your western blot experiments.
Which to pick: Only one Boster MASP2 antibody, A02323-1, is listed here; it includes an actual western blot validation image, so it's the clear choice for your WB experiments—no alternative SKU is currently available.
Source: BosterBio MASP2 gene-info card — filtered to Western-blot-capable antibodies; each card shows that product's actual WB validation figure.
References
- UniProt Consortium. UniProt entry O00187.
- Human Protein Atlas. MASP2 tissue expression.