Heat-Stable Recombinant Human FGF-basic Protein

What it means: This FGF2 is produced in Human cells rather than in E. coli or insect cells. The manufacturer states the host as human cells and does not name a specific cell line for this product.

Why it matters:

• Production in a human host avoids bacterial host-cell contaminants that can affect sensitive stem-cell and organoid cultures.
• It fits fully human, xeno-free culture systems, together with the animal-free manufacturing format.
• The protein is supplied tag-free and carrier-free, so the expression host is the main source-related variable.

How to interpret here: An expression system of Human cells means the FGF2 was made by a human cell line. It is intended for FGF2-dependent work such as human iPSC/ESC maintenance, progenitor expansion and organoid culture.

Tip: When switching from an FGF2 made in another host or from a different stabilized variant, re-titrate the working concentration.

What it means: This product is a Heat-Stable FGF2. It is designed to keep FGF2 signaling more constant during extended cell culture, where the protein spends long periods at culture temperature.

Why it matters:

• Native FGF2 is sensitive to prolonged incubation under cell-culture conditions, so signaling can fall between medium changes.
• A more stable FGF2 can help keep culture conditions steadier over longer feeding intervals in FGF2-dependent workflows.
• Stabilized FGF2 variants are not interchangeable at the same dose, because potency and signaling behaviour can differ between them.

How to interpret here: Heat-Stable here describes stability under cell-culture conditions. The manufacturer does not publish a quantitative retained-activity time, so performance should be confirmed in the culture system used.

Tip: Heat-Stable does not mean the protein can be autoclaved, heat-sterilized or used for heat processing or therapeutic hyperthermia.

What it means: The protein is Tag-free: no His, Fc, GST or other affinity tag is fused to the FGF2 sequence, and no tag needs to be removed before use.

Why it matters:

• A tag adds extra amino acids that can change folding, receptor binding, stability or the apparent molecular weight of a small signaling protein.
• In defined stem-cell and organoid media, every added component is a variable; a tag-free protein keeps the ligand as close as possible to the native sequence.
• Tag-free proteins are also preferred when results will be compared with published protocols that used untagged growth factors.

How to interpret here: Tag-free here means the vial contains only the FGF2 protein. It cannot be captured or detected with anti-His, anti-GST or Protein A reagents, so detection needs an antibody against FGF2 itself.

What it means: Purity of >95% by SDS-PAGE means that when the protein is run on a denaturing gel and stained, at least 95% of the stained protein is the FGF2 band. It is the release specification the manufacturer applies to every lot.

Why it matters:

• High purity limits other proteins in the vial that could act on cells or interfere with downstream readouts.
• Dosing is done by protein mass, so a pure preparation makes the amount of active ligand added more accurate and comparable between experiments.
• Purity is measured together with endotoxin (<0.5 EU/µg) and biological activity before each lot is released.

How to interpret here: A specification of >95% by SDS-PAGE is a minimum value. The exact result for each lot is on the Certificate of Analysis (CoA), available from BioHippo on request.

Tip: SDS-PAGE purity shows how clean the preparation is, not how active it is; check the activity data separately.

What it means: The species is Human: the amino-acid sequence is that of human FGF2 (FGF-basic, bFGF), in its low-molecular-weight form. The protein is also produced in human cells, so both the sequence and the expression host are human.

Why it matters:

• Matching the species of the growth factor to the species of the cells avoids differences in receptor affinity between species.
• Human sequence is the usual choice for human iPSC, ESC, organoid and primary human-cell work.
• Recording the species in protocols matters because the same protein is sold from several species by many suppliers.

How to interpret here: Human here refers to the protein sequence. When reproducing a published protocol, check that the protocol also used Human FGF2; if it used a protein from another species, the working concentration may need adjusting.

What it means: The protein is supplied Lyophilized, that is freeze-dried to a powder, from a 0.2 µm-filtered PBS solution and without carrier protein.

Why it matters:

• Lyophilized protein is more stable during storage than a solution, which gives a long shelf life when stored correctly.
• The stock concentration is set at reconstitution, so it can be matched to the volumes used in the protocol.
• As supplied, store at −20°C to −80°C for up to 12 months from receipt; after reconstitution keep it at 2°C to 8°C for up to 1 month or at −20°C to −80°C for up to 3 months.

How to interpret here: Lyophilized means the vial must be reconstituted before use: briefly centrifuge the vial before opening, then reconstitute in sterile PBS containing 0.1% endotoxin-free recombinant human serum albumin, mix gently without aggressive vortexing and prepare single-use aliquots under sterile conditions.

Tip: Avoid repeated freeze–thaw cycles of the reconstituted protein; a manual-defrost freezer is recommended.

What it means: The molecular weight is Approximately 17 kDa. The manufacturer describes the protein as the low-molecular-weight form of FGF2, supplied as a monomer.

Why it matters:

• Molecular weight is the first check of identity when the protein is run on a gel.
• The low-molecular-weight form is the FGF2 commonly used in stem-cell and cell-culture protocols, so the value helps confirm that form.
• The manufacturer gives a nominal value and refers to lot-level documentation for exact data.

How to interpret here: Approximately 17 kDa is a nominal value. Refer to the lot-specific Certificate of Analysis (CoA), available from BioHippo on request, for the data that apply to each lot.

Tip: If a gel band differs slightly from Approximately 17 kDa, compare it with the CoA for that lot before drawing conclusions.