- Other Names
Covance Catalog# PRO-133P
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- Product Citations
Posi-Tag is a recombinant protein that contains 12 different tags. It has a predicted weight of 45 kDa and is intended for use as a positive control in western blot applications. The lysate contains the commonly used epitope tags HA, c-myc, Glu-Glu, GST, 6-His, HSV, T7, V5, VSV, E-tag, S-tag, and FLAG™ tag.Product Details
- Bacterial lysate in loading buffer.
- Dilute Posi-Tag 1:20 in SDS-PAGE loading buffer containing 5% 2-Mercaptoethanol. Boil for 5 minutes at +95°C before loading.
- Storage & Handling
- Store at -20°C or below. Upon initial thawing, apportion into working aliquots and store at -20°C or below. Avoid repeated freeze-thaw cycles to prevent denaturing the protein. May be stored at 2-8°C for short periods.
WB - Quality tested
- Recommended Usage
Each lot of this antibody is quality control tested by Western blotting. For Western blotting, the suggested use of this reagent is 0.5 - 2.0 µL. It is recommended that the reagent be titrated for optimal performance for each application.
- Application Notes
This protein is effective as a positive control for epitope tag antibodies in immunoblotting.
Our Posi-Tag protein lysate contains the commonly used epitope tags: HA, c-myc, Glu-Glu, GST, 6-His, HSV, T7, V5, VSV, E-tag, S-tag, FLAG (TM). These proteins were fused in the following order, GST, T7, HSV, c-myc, VSV, Glu-Glu, V5, E-tag, DYKDDDDK, S-tag, HA, and 6-His.
*Predicted MW = ~45 kD
FLAG is a trademark of Sigma-Aldrich Co.
- Biology Area
- Cell Biology
- Gene ID
- View information about Posi-Tag on UniProt.org
- Does specific activity of a recombinant protein vary between lots?
Specific activity will vary for each lot and for the type of experiment that is done to validate it, but all passed lots will have activity within the established ED50 range for the product and we guarantee that our products will have lot-to-lot consistency. Please conduct an experiment-specific validation to find the optimal ED50 for your system.
- Have your recombinants been tested for stability?
Our testing shows that the recombinant proteins are able to withstand room temperature for a week without losing activity. In addition the recombinant proteins were also found to withstand four cycles of freeze and thaw without losing activity.
- How do you convert activity as an ED50 in ng/ml to a specific activity in Units/mg?
- Use formula Specific activity (Units/mg) = 10e6/ ED50 (ng/mL)
- How does the activity of your recombinant proteins compare to competitors?
We quality control each and every lot of recombinant protein. Not only do we check its bioactivity, but we also compare it against other commercially available recombinant proteins. We make sure each recombinant protein’s activity is at least as good as or better than the competition’s. In order to provide you with the best possible product, we ensure that our testing process is rigorous and thorough. If you’re curious and eager to make the switch to BioLegend recombinants, contact your sales representative today!
- What is the specific activity or ED50 of my recombinant protein?
The specific activity range of the protein is indicated on the product datasheets. Because the exact activity values on a per unit basis can largely fluctuate depending on a number of factors, including the nature of the assay, cell density, age of cells/passage number, culture media used, and end user technique, the specific activity is best defined as a range and we guarantee the specific activity of all our lots will be within the range indicated on the datasheet. Please note this only applies to recombinants labeled for use in bioassays. ELISA standard recombinant proteins are not recommended for bioassay usage as they are not tested for these applications.