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PGF · Western blot design guide
Design a Western Blot for PGF
Real validated PGF Western blot protocols, expected-band and isoform facts, troubleshooting for weak or shifted signal, and recommended anti-PGF WB antibodies. Everything you need to plan the experiment before you commit precious samples.
Last reviewed: May 2026 · Scientific review: Boster Bio technical team
PGF 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 | ~24.8 kDa | |
| Observed band | ~25 kDa | |
| Gel | 12–15% | |
| Negative control | siRNA / KO lysate |
Important caveats
Reasons your observed band may differ from the expected size.
| PTM | Glycosylated + Cleaved | |
| Caveat | N-glycosylation adds mass | |
| Regulation | Hypoxia up | |
| Isoform | 4 isoform(s) |
Section 1
Real Curated PGF Western Blot Protocols
Literature-validated Western blot parameters for PGF — gel percentage, transfer, blocking, antibody incubation and detection, extracted from published methods.
| Sample / lysate | human T-47D . 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-PGF antigen affinity purified polyclonal antibody (Catalog # A01164-2) 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 1:10000 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 PGF at approximately 25KD. The expected band size for PGF is at 25KD |
| Gel % | 12–15% |
| 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, 1:10000 |
| Wash | TBS-0.1% Tween, 3 × 5 min |
| Detection | ECL |
| Exposure / imaging | Tanon 5200 |
| Observed band | 25 kDa |
Section 2
What Is the Expected PGF Western Blot Band Size?
PGF has a 24.8 kDa predicted backbone but runs at ~25 kDa due to N-glycosylation, with a ~50 kDa disulfide-linked homodimer band possible if reduction is incomplete.
| single band near 25 kDa under reducing conditions | glycosylated monomeric mature PlGF after signal-peptide cleavage, matching the ~25 kDa empirical band |
| band near 50 kDa under non-reducing or incompletely reducing conditions | disulfide-linked antiparallel PlGF homodimer held together by inter-chain disulfide bonds |
| band running above the 24.8 kDa predicted mass, sometimes slightly smeared | added carbohydrate mass from N-linked glycosylation at Asn33 and Asn101 |
| mature band slightly smaller than the unprocessed full-length precursor | cleavage of the 18-residue N-terminal signal peptide to generate secreted mature PlGF |
| little or no band in unconditioned whole-cell lysate | PlGF is secreted and released from the cell, so intracellular pools can be low except for cell-attached PlGF-2 |
| multiple bands at different apparent sizes | co-expression of the alternatively spliced isoforms PlGF-1, PlGF-2, PlGF-3, and PlGF-4, which differ in length |
💡Expected PGF appearanceUnder reducing SDS-PAGE, expect a single glycosylated monomeric PlGF band at approximately 25 kDa, close to the 24.8 kDa predicted mass, with a ~50 kDa disulfide-linked homodimer band appearing if reduction is incomplete.
| predicted mass from UniProt | sets the baseline expectation of 24.8 kDa for the unmodified 221-aa polypeptide |
| N-glycosylation at Asn33 and Asn101 | adds carbohydrate mass, shifting the apparent monomer band up to the observed ~25 kDa and potentially broadening it |
| inter-chain disulfide homodimer formation | under non-reducing or incompletely reducing conditions, roughly doubles the apparent size versus the ~25 kDa monomer |
| signal-peptide cleavage (residues 1-18) | removes the N-terminal signal sequence so mature secreted PlGF runs smaller than the unprocessed precursor |
| alternative splice isoforms (PlGF-1, PlGF-2, PlGF-3, PlGF-4) | differing isoform lengths can add extra bands of varying apparent size, and PlGF-3 can appear as both monomer and homodimer |
| Situation | Likely cause | Next action |
|---|---|---|
| No band in lysate | PlGF is secreted and largely released from the cell rather than retained intracellularly | probe concentrated conditioned media or a secretion-focused prep in addition to whole-cell lysate |
| Band higher than expected | incomplete reduction leaves the inter-chain disulfide-linked homodimer intact near double the ~25 kDa monomer | increase reducing agent concentration and boil samples longer before loading |
| Broad smear instead of sharp band | heterogeneous N-linked glycosylation at Asn33 and Asn101 | treat with PNGase F to remove N-glycans and compare against a deglycosylated control for a sharper band |
| Multiple bands | co-expression of the four alternatively spliced isoforms PlGF-1, PlGF-2, PlGF-3, and PlGF-4 | confirm isoform identity with isoform-specific reagents or transcript data before calling extra bands nonspecific |
| Weak or no signal | PlGF-2 remains cell-attached unless released by heparin, so standard extraction may under-recover it | include a heparin or heparin-mimetic elution step during sample preparation |
| Fragments below expected size | proteolytic degradation of the secreted growth factor during handling | add protease inhibitors and process samples cold throughout lysis |
Experiment evidence
Western blot images showing PGF band
A01164-2 · PGF
← swipe / scroll for more images →
Real WB data behind the band-size expectations in this section.
Sample controls for PGF Western blot
🧪For positive controls for PGF in Western blot, you can use placental tissue lysate, since PGF (placenta growth factor) is characteristically expressed by placental trophoblast and is the tissue the protein is named for.
Positive control: Placenta
Negative control: ubiquitously expressed; use siRNA knockdown or KO line
Loading controls: Run GAPDH and β-actin as housekeeping loading controls alongside a total-protein stain (e.g., stain-free gel, Ponceau S, or REVERT) to confirm equal loading and transfer.
⚠️Feasibility: PGF is secreted (with PlGF-2 remaining partly cell-attached unless heparin-released), so whole-cell lysates may give weak signal and conditioned medium or heparin-eluted fractions should be tested alongside cell lysate for reliable detection.
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 |
|---|
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|
Section 3
Advanced PGF Western Blot Tips
Deeper troubleshooting and optimisation questions for PGF, answered from its protein features.
Why does PGF run close to its predicted mass?
Mature PGF, after cleavage of its 18-residue signal peptide, carries 2 N-glycosylation sites and 5 disulfide bonds but no other listed PTMs, so glycosylation adds little mass. Reduced, denatured monomer therefore runs near the 24.8 kDa predicted mass, consistent with the ~25 kDa observed band.
Which PGF isoform does the antibody likely detect?
PGF has four alternatively spliced isoforms (PlGF-1 to -4) differing in heparin-binding regions. PlGF-2 stays cell-attached unless released by heparin, while PlGF-1, -3 and -4 are freely secreted. Check the antibody's epitope location and whether lysate or conditioned medium was used, since isoform recovery differs between the two.
Could a disulfide-linked homodimer appear on non-reducing gels?
PGF is normally an antiparallel homodimer, disulfide-linked, and can also pair with VEGFA. Under non-reducing conditions expect a band near double the monomer mass; adding a reducing agent and boiling before loading collapses this to the ~25 kDa monomer, confirming the shift is disulfide-driven, not a separate isoform.
What signaling induces PGF expression in tissue samples?
PGF is annotated as a growth factor involved in angiogenesis and cell differentiation, expressed in placental and vascular tissue. As a VEGF-family angiogenic factor it is expected to rise under hypoxic or ischemic conditions relative to normoxic controls; use matched tissue/hypoxia controls when interpreting induction changes.
How should blocking be optimized for PGF detection?
PGF is a heparin-binding glycoprotein, so avoid heparin-containing or heavily sulfated blocking reagents that could compete for its binding surface. Standard BSA or non-fat milk in TBST is adequate; ensure thorough washing to remove residual glycan- or heparin-interacting contaminants that could otherwise raise nonspecific background.
What transfer method to use for PGF Western blot?
Given PGF's small ~25 kDa mature size and 5 disulfide bonds, use semi-dry or wet transfer to PVDF with fully reduced, denatured samples and a shortened transfer time suited to low-molecular-weight proteins, avoiding blow-through while ensuring complete transfer of this small secreted glycoprotein.
What loading control suits secreted PGF samples?
Because PGF is secreted, intracellular housekeeping proteins like GAPDH or actin are unsuitable for normalizing conditioned media or serum. Use a total protein stain such as Ponceau S or a stain-free gel, or normalize to input volume or cell number instead.
What explains an unexpected higher molecular weight PGF band?
A higher-mass band can reflect incomplete reduction of the disulfide-linked homodimer, appearing near double the monomer size, or heterodimer formation with VEGFA, which PGF is known to form. Confirm by rerunning under fully reducing, denaturing conditions and comparing against a monomer-only control.
Boster reagents
Best PGF Western Blot Antibodies
BosterBio's PGF 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-PGF Antibody Picoband®
Cat # A01164-2
Our recommended anti-PGF antibodies are top-performing reagents selected for strong literature citation, rigorous validation, and orthogonal cross-validation against negative tissue controls and complementary detection methods, giving you confidence in specific, reproducible PGF detection by western blot.
Which to pick: Only one PGF antibody is catalogued here: A01164-2, which includes an actual western blot validation image demonstrating specific PGF detection. With no alternative SKUs listed, A01164-2 is the recommended choice for your western blot experiments.
Source: BosterBio PGF gene-info card — filtered to Western-blot-capable antibodies; each card shows that product's actual WB validation figure.
References
- UniProt Consortium. UniProt entry P49763.
- Human Protein Atlas. PGF tissue expression.