Product FAQ

Can I filter sterilize cell culture medium containing Gibco Recombinant Proteins?

Answer

Yes, cell culture medium containing low concentrations of proteins can be filter-sterilized if needed. We recommend the use of a low-protein-binding 0.22 micron filter.

Answer Id: E5578

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Product FAQ

Some of the Gibco Recombinant Proteins are not biologically active. Can these be used for cell culture?

Answer

No, cell culture usage requires biologically active protein. These proteins are for use as a protein standard or immunogen.

Answer Id: E5572

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Product FAQ

Are a "unit" and an "International Unit" value for a Gibco Recombinant Protein the same thing?

Answer

No, the Gibco activity value has not been calibrated against the WHO standards given by the NIBSC.

Answer Id: E5577

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Product FAQ

It doesn't look like there is any product in my vial. Is this a normal appearance of the Gibco Recombinant Proteins?

Answer

Yes, the proteins do not have a carrier protein so the pellet is transparent. In addition, the protein may be lodged in the cap, so the vial should be spun down before opening. After reconstituting the protein, a protein assay will confirm the pellet was in the vial.

Answer Id: E5581

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Product FAQ

What is the ED50 of a Gibco Recombinant Protein?

Answer

The ED50 value is defined as the protein concentration that shows a 50% maximal response.

Answer Id: E5579

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Product FAQ

How is the Gibco Recombinant Protein purity determined?

Answer

Protein purity (to 95%) is determined by SDS-PAGE.

Answer Id: E5582

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Product FAQ

Why is the ED50 for Gibco Recombinant Proteins given as a range?

Answer

ED50 values are provided as a range because of variability in the bioassay used to determine ED50 values. For calculations using the ED50, we recommend to use the midpoint of the range.

Answer Id: E5576

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Product FAQ

Are Gibco Recombinant Proteins cross-reactive with other species?

Answer

Cross-reactivity depends on the protein and species. In general, human proteins are often active on mouse cells. Many mouse proteins are active on human cells, but they may show a different specific activity than the human protein.

Answer Id: E5580

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Product FAQ

How do I convert the ED50 of a Gibco Recombinant Protein from ng/mL to units/mg?

Answer

To convert the units, you need to know midpoint of the ED50 range for this calculation:

1x10E6 / ED50 midpoint (ng/mL) = ED50 (units/mg)

Answer Id: E5575

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Product FAQ

How should Gibco Recombinant Proteins be stored?

Answer

Store lyophilized Gibco Recombinant Proteins for 1 year at 4°C. After reconstitution, store the stock solution at -5 to -20°C for up to three months in single use aliquots (generally 10-20 uL in polypropylene tubes). Do not allow multiple freeze-thaw cycles. Do not store dilute solutions.

Answer Id: E5573

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Product FAQ

Why is BSA required when making a dilute solution of Gibco Recombinant Proteins?

Answer

When making dilute solutions of Gibco Recombinant Proteins, a carrier protein like bovine serum albumin (BSA) is required to minimize the protein binding to the surface of plasticwear.

Answer Id: E5571

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Product FAQ

What concentration of bovine serum albumin (BSA) do I need to use in dilute solutions of Gibco Recombinant Proteins?

Answer

When making dilute solutions of Gibco Recombinant Proteins, a carrier protein is required to minimize the protein binding to the surface of plasticwear. BSA is generally used at 0.1 %, but sometimes as high as 1%.

Answer Id: E5570

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Product FAQ

How should Gibco Recombinant Proteins be reconstituted?

Answer

Depending on the product, the reconstitution instructions appear on the Certificate of Analysis or in the Product Manual. Both can be found on the website by searching the product number or lot number directly in the search box at the top of the page. Generally, Gibco Recombinant Proteins can be suspended in solvent to make a stock solution of 0.1 - 1.0 mg/mL. If BSA is required as a carrier protein, the reconstitution instruction will indicate it. BSA is usually not required in concentrated solutions.

Answer Id: E5569

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Product FAQ

What is the difference between Gibco GlutaMAX and glutamine supplements?

Answer

GlutaMAX-I supplement is an improved cell culture supplement that can be used as a direct substitute for L-glutamine in your cell culture medium. Please go here to read more about the properties of GlutaMAX supplement (https://www.thermofisher.com/us/en/home/life-science/cell-culture/mammalian-cell-culture/media-supplements/glutamax-media/glutamax-vs-glutamine.html).

Answer Id: E11884

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Product Literature

Brochure: BenchStable Media