Qk025 recombinant human FGF2 (bFGF)
Protein quality information for Qk025 batch #012
Protein is provided in PBS without carrier protein. Protein concentration is 1 mg/ml.
All our proteins are produced in-house by our scientists and we provide detailed quality data for each individual batch. Please contact us any time by email firstname.lastname@example.org or phone +44 (0) 1223 491486 if you have any questions.
After aliquotting the protein, we choose a vial at random and dilute as recommended to ensure we are testing as close to the protein you will receive as possible. Biochemical identity and purity of each batch is checked using SDS-PAGE, mass spectrometry and analytical reverse phase chromatography. We use a sensitive test to ensure endotoxin levels are at industry leading low levels (<0.01 EU per µg protein). We also check that the correct amount of protein is recovered from the vial – it might sound basic but if you order 100 µg, we believe you should receive 100 µg.
Result: FGF2 migrates as major band at 17 kDa in non-reducing (-βME) conditions and upon reduction (+βME). The higher molecular mass band at 35 kDa is a dimer that we always see in our highly purified human FGF2, the presence of this does not affect biological activity.
Purified recombinant protein (7 µg) was resolved using 15% w/v SDS-PAGE in reduced (+β-mercaptothanol, R) and non-reduced conditions (NR) and stained with Coomassie Brilliant Blue R250.
Result: calculated molecular mass of FGF2 is 16310 Da. Molecular mass from this analysis is 16310 Da, consistent with the calculated mass. The calculated molecular mass of dimeric protein is 32620 Da and this is represented in the mass spec with average molecular mass 32617 Da.
MALDI mass spectrometric analysis is used to confirm the molecular mass of the intact protein and to reveal any heterogeneity that would not be evident in SDS-PAGE analysis. The results are compared with calculated mass of the protein with the assumption that all the cysteines are disulphide-linked. The different peaks represent different charge states of the protein.
Result: UV spectrum shows full recovery of protein following aliquoting and lyophilisation.
Absorbance at 280 nm: average 0.112
Recovered concentration:0.112 cm-1 x 10 /0.98 cm-1 mg ml-1 = 1.1 mg / ml
Recovery: 110% (>100% due to routine 10% over-fill of vials during aliquoting)
The sample was diluted 1:10 in 100 mM sodium phosphate pH 7.4 and the UV spectrum 340-220 nm measured in duplicate. Concentration was calculated using extinction coefficient at 280 nm
Result: Endotoxin level <0.005 EU/ug protein (below level of detection)
Stem cell cultures are sensitive to endotoxins1, which can be present in media, serum and as a contaminant on plasticware. We optimise our protein production processes to ensure the lowest possible levels of endotoxin contamination. Our endotoxin pass criteria are set at the industry leading <0.1 EU per ug protein and we aim for <0.01 EU per ug protein. Endotoxin levels in our proteins are determined by an external expert microbiological testing services provider.