Recombinant human bone morphogenetic protein-7 (rhBMP-7 / OP-1): preparation and storage
Intended for research use only. Not a medicinal product.
Contents (8 sections)
Check the dimer, not only the name
R&D Systems describes 354-BP as CHO-derived human BMP-7, residues Ser293–His431, in a disulfide-linked homodimer. The record distinguishes predicted monomer mass from SDS-PAGE bands under reducing conditions. These are different measurements, not a reason to choose a convenient number arbitrarily. [1]
For your LOT, establish whether the supplied material is a mature domain, another construct or a complex containing additional regions. Do not apply full-precursor mass to a purified domain. A molarity calculation for the active dimer requires a defined molecular counting unit.
Why the manufacturer example uses an acidic vehicle
For 354-BP/CF, the manufacturer specifies sterile 4 mM HCl at 100–200 µg/mL. Carrier-containing 354-BP additionally requires at least 0.1% albumin. Even two forms of the same protein have separate instructions. These numbers describe R&D products, not every BMP-7 reagent. [1]
The example demonstrates why “just add water” is incomplete; it does not prescribe acid for your vial. Check your own specification, lyophilizate composition and assay. Replacing acidic vehicle with neutral buffer or adding BSA changes the protocol and requires evaluation.
Transfer into medium is a separate compatibility check
After reconstitution, reproduce the dilution in the actual cell or analytical medium. Check final pH, acid concentration and protein additives. A clear acidic stock does not establish clarity after neutralization or preservation of the active form.
Use the permitted mixing method; do not add reducing agents to a disulfide-linked protein without a method-based reason. If particles appear, record the step where they arise. Filtration can change recovered quantity, so starting mass alone no longer establishes final concentration.
Dilution arithmetic and the monomer-mass error
For an educational example, dilute 100 µg/mL to 100 ng/mL, an overall 1:1000 factor. Two calculated steps are possible: bring 10 µL to 1 mL to obtain 1 µg/mL, then bring 100 µL of that intermediate to 1 mL. This is arithmetic, not a recommended BMP-7 concentration.
For molarity, specify whether monomers or dimers are counted. Using monomer mass while reporting dimer quantity gives a different result. The expressed construct also matters. BSA mass does not become BMP-7 mass merely because both proteins occupy the vial.
Activity means a defined cell system and endpoint
R&D measures 354-BP activity through induction of alkaline phosphatase in ATDC5 cells. This is not a general test of any “regeneration” claim or an automatic criterion for another model. Define your endpoint and reference material before comparing batches. [1]
Reducing and non-reducing SDS-PAGE, chromatography and functional assays address different material properties. High purity does not predetermine activity. If a signal falls, compare fresh and stored samples within one run and check cells, timing and vehicle.
Dry protein and a reconstituted sample
R&D specifies frozen storage as supplied and separate conditions after reconstitution. Its refrigerated period requires sterile conditions; it does not authorize storing every BMP-7 reagent for the same duration. Another manufacturer instruction is not your LOT COA. [1]
Apply “freezer for the long term, refrigerator for short use” to dry material only where its specification permits it. A refrigerated week or month needs supporting evidence. Solutions need vehicle- and concentration-specific data; when freezing is allowed, use aliquots instead of repeatedly thawing the whole stock.
Record temperature excursions, extra mixing, transfers and filtration. This history helps explain functional changes and prevents unnoticed mixing of samples with different storage histories.
Frequently asked questions
Are monomer and active dimer equivalent?
No. The method must define the molecular unit used in molar reporting.
Why is bacteriostatic water not a complete answer?
It does not define the required pH, concentration or protein additives, which depend on the supplied BMP-7 form.
Does an ALP assay replace an identity test?
No. It measures a response under defined conditions; molecular identity needs separate confirmation.
Sources
- R&D Systems: Recombinant Human BMP-7, 354-BP and 354-BP/CF. Construct, dimeric form, formulations, activity and storage read 26 October 2026; another manufacturer conditions do not transfer automatically.
Product and current sizes · Monograph and research · COA
A laboratory guide for research material; no human-use regimen is provided.
End of article
BMP-7 (OP-1)
for laboratory research
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