Recombinant Protein FAQs

Recombinant protein FAQs

1. Do recombinant protein tags affect protein activity?

It is different from case to case. For some applications, small tags, such as His-tag and FLAG-tag, may not affect protein activity and do not need to be removed. For example, there are more than 100 structures of His-tagged proteins in the Protein Data Bank. This indicates that the small His-tag often do not interfere with correct protein folding. If there is no activity data online and activity is crucial to your experiments, please feel free to contact us at

2. Which dilutions of the recombinant protein should I use in my experiment?

Dilution suggestions for our recombinant proteins are available in the datasheet provided for each product. Please remember that these dilutions and concentration estimates are simply recommended as a starting point, and it may be necessary to adjust the dilution based on the experimental results.

3. Can I use Antibody Genie recombinant proteins in/on humans?

Our proteins are intended strictly for research and laboratory purposes only.

4. What is the endotoxin level/LPS level of Antibody Genie recombinant proteins?

Proteins that have a biological activity section mentioned in our data sheet were tested for the LPS levels and they can be used in cell culture / in-vitro experiments. If there is no biological activity mentioned, you will need to assess the final endotoxin levels in the protein sample prior to the experiment.

5. I cannot physically visualize powder in the vial, is protein present in the vial?

Please centrifuge vial prior to opening to ensure the product is not near the cap. One cannot asses presence of a protein by naked the eye visualization. We lyophilize our proteins using minor buffer concentrations therefore one cannot visualize the protein in the vial. The protein is present in the vial and is spread across the vial walls.

6. How do I reconstitute or dilute the protein?

If the protein is lyophilized you should use our reconstitution recommendations in the data sheet provided. If the protein is in liquid form, we recommend to further dilute the protein using the same formulation as published in our data sheet.

7. Can Antibody Genie recombinant proteins be used for in vivo experiments?

Yes, for research purposes only, not diagnosis.

8. Can I use Antibody Genie recombinant proteins in an untested application or species?

Yes, but because the protein has not been tested for that specific application, there is a risk that the protein may not work for the application or species.

9. What is the expiry date of your proteins?

Our proteins are stable for at least 12 months from the date of its export at the mentioned storage conditions prior to its reconstitution.

10. How long is the protein stable after reconstitution?

We do not obtain stability data after the protein has been reconstituted over different periods of time. We highly recommend adding a carrier protein such as albumin.

11. How should my protein be centifuged?

After receiving your protein, centrifuge the samples for 3 minutes at 12,000 rpm and 4℃. Remove and open the tube lid for aliquoting and dissolution before storing (if the protein volume exceeds 50 μL, extend the centrifugation time to 5 minutes to guarantee the reclamation of all recombinant protein).

12. How should I store my protein long-term?

  • For long-term storage of most antibodies, -20℃ is recommended.
  • Prolong protein activity by avoiding freeze/thaw cycles as much as possible. You may also reduce the possibility of contamination caused by taking protein from the same vial several times by avoiding aliquoting.
  • To preserve your protein, aliquoted amounts should be just enough for one experiment and no less than 10 μL each. Protein concentration may be influenced by evaporation and adsorption to the vial wall if the aliquoted amount is less than 10 μL.
  • If thawed antibodies aren’t used up all at once, store the rest of the protein liquid at 4℃ to avoid refreezing.
  • Protein working liquid should be made and used on the same day. Do not store for more than one day at 4℃.
  • Always avoid storing antibodies in an automatic defrost refrigerator/freezer. Automatic defrost cycles cause dramatic changes in the interior temperature of these freezers. If storage in this kind of freezers is absolutely necessary, place the protein near the center of the refrigerator – the highest temperature fluctuations occur near the door and walls of the freezer.

13. How do I store my protein short-term?

  • The activity of most recombinant proteins will not be adversely affected when stored at 4℃ for 1-2 weeks.
  • If the proteins are to be used within 1-2 weeks, the recommended storage temperature is 4℃. Make sure to avoid freeze/thaw cycles.
  • The best long-term storage should be -20℃. Kindly refer to your protein’s specifications for proper storage procedures.

14. How should I aliquot my antibody?

Antibody Genie does not recommend researchers to aliquot the antibody products because it will cause evaporation, condensation dilution, adsorption, and other processes that will affect the concentration and effectiveness of the antibody. The smaller the individual aliquots, the larger the loss.