PIPETTE TIP 100-1000UL NATURAL

Protein purity is most often determined by SDS-PAGE; sometimes, it is analyzed by HPLC as well. Please refer to either the product manual, data sheet or certificate of analysis (CoA) for product-specific purity levels and methods.

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.

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

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

For additional information on ED50, please refer to our Tech Tip: https://assets.thermofisher.com/TFS-Assets/BID/Technical-Notes/converting-ed50-ng-ml-specific-activity-units-mg-tech-note.pdf

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.

The specific activity of a bioactive protein can be determined using the following equation:
1 x 10E6 / ED50 (ng/mL) = specific activity (units/mg)

The ED50 can be found on the CoA for the recombinant protein, but we advise determining the ED50 of a given recombinant protein in your particular functional assay system.

For additional information on ED50, and its relationship with specific activity, please refer to our Tech Tip: https://assets.thermofisher.com/TFS-Assets/BID/Technical-Notes/converting-ed50-ng-ml-specific-activity-units-mg-tech-note.pdf