Recombinant Protein from HEK293 FAQs
1. What kind of protein expression system does OriGene use?
OriGene expresses and purifies from only mammalian cells and we primarily use Hek293T cells, a line derived from human embryonic kidney. We do offer custom options of purifying from different Hek293 lines or CHO cells
2. What is the OriGene guarantee for purified proteins?
OriGene guarantees that the purified protein will show at least 80% purity by SDS-PAGE/Coomassie staining, will contain <0.1EU/ug of endotoxin, will be fully soluble at a minimum concentration of 50ug/ml, and that the preparation will not contain any detectable protease, DNase, or RNase activity.
3. Where can I find the concentration of the purified protein that I received?
The concentration of the purified protein is determined by BCA assay (Pierce) and is on the tube and the Certificate of Analysis. In conjunction with the lot number from the tube, the concentration can serves as an indicator for this specific purification.
4. The standard size offered is 20µg and this is not enough for my assays. Can I order a larger amount?
On OriGene’s webpage for each specific protein there is an option “Larger amount”. Just click this button and complete the easy-to-use form
5. What is the stability of OriGene’s purified protein?
OriGene guarantees that the protein will remain stable for up to three months after receipt pending appropriate storage and handling.
6. What are the recommended storage and handling conditions for protein samples?
Store at –80C. Thaw on ice, aliquot to individual single-use tubes, and then re-freeze immediately. Only 2-3 freeze thaw cycles are recommended.
7. Does OriGene guarantee the function of the purified protein in all assays?
OriGene cannot guarantee that all proteins will retain all putative functions due to the large number of variables involved, e.g. essential co-factors may not be co-purified. OriGene has taken several steps to preserve maximum functionality: only small epitope tags (Myc-DDK*) were fused to the protein, all proteins are fully soluble in the final buffer, and all are expressed in mammalian cells.
8. Is a stabilizing agent added to the purified protein?
The final buffer for all proteins contains 10% glycerol as a stabilizing agent.
9. What buffer is the protein provided in?
The final buffer composition is: 10% glycerol, 100mM glycine, 24mM Tris-HCl, pH 7.3.
10. What method does OriGene use to purify the proteins?
All proteins are purified using an anti-DDK immunoaffinity column.
11. Will the Myc-DDK tag affect the function of protein?
OriGene cannot guarantee that the epitope tags will not affect the protein’s functions but we have specifically selected the Myc-DDK epitopes as they are very small (only 3kDa total) and are fused to the C-terminus to prevent interference with N-terminal signal peptide sequences required for organelle targeting.
12. OriGene has informed me that my protein cannot be purified by their standard method. What are my options?
If OriGene fails to purify a protein using our standard method, we do not charge any fee and you can simply cancel the order. If the protein is essential but purity is less of an issue, we can often supply a whole cell lysate or a partially purified preparation of the overexpressed protein at a significant discount. Please contact our technical support team at firstname.lastname@example.org for information on this option. Although we cannot provide this purified protein using our standard approach, we might be able to supply it as a custom purification. For information on this service, please contact email@example.com.
13. What do I do if I can't find my protein of interest?
OriGene is routinely adding new proteins on a quarterly basis. Please check our website frequently or fill out our custom service form. OriGene will contact you to discuss your needs in detail.
14. What source do you use for the predicted molecular weight of the antigen?
We mainly use the swissprot webpage to help predict the molecular weight of unprocessed protein. Please see the following link: ExPASy Link
15. If the coomassie gel shows a protein of a molecular weight different from the predicted molecular weight, does this mean I received the wrong protein?
The predicted the molecular weight is calculated from the protein primary amino acid composition. There could be some discrepancy from the actual molecular weight, if there were post-translational modifications or known proteolytic activity. In this case, OriGene strongly suggests researchers check related literature on this particular protein.
16. I need to cite your product for a paper I am writing. What language should I use?
We recommend that you refer to the product by its specific catalog number and refer to us as OriGene Technologies (Rockville, MD). Furthermore, we'd love to hear from you when your paper is published. Inform us and we will send a gift.
17. How do I prepare recombinant proteins for cell culture purpose?
We recommend all proteins be diluted into cell culture medium at required concentrations, and go through a 0.2 u sterile filtration step before being applied to cell culture