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Recombinant Proteins FAQs
More Cell and Gene Therapy related FAQs: Cell Cryopreservation FAQs | PRIME-XV T Cell CDM FAQs | PRIME-XV MSC XSFM FAQs | PRIME-XV NK Cell CDM FAQs | PRIME-XV MSC XSFM Dual Component Kit FAQs
Q. What is the intended use of Shenandoah CTGrade GMP Recombinant Proteins?
A. Shenandoah CTGrade GMP Recombinant Proteins are for research or further manufacturing use only. Not for injection or diagnostic procedures. The safety and efficacy of these recombinant proteins in diagnostic or other clinical procedures has not been established. Refer to the Product Insert.
Q. What is the intended use of Shenandoah Recombinant Proteins?
A. These proteins are for research use only.
Q. What cell types are Shenandoah Recombinant Proteins generally used for?
A. Shenandoah recombinant proteins can be used to induce proliferation in various cell types, including primary cells for expansion and differentiation, stem cells, such as induced pluripotent stem cells (iPSCs) and embryonic stem cells (ESCs) and immune cells, like T cells and natural killer (NK) cells.
Q. What is the difference between IL-2C126S and native IL-2?
A. IL-2C126S is not glycosylated because it is derived from E.coli and has an amino acid sequence that is identical to that of Proleukin. The amino acid serine is substituted for cysteine at position 126.
Q. Are there SDS for the recombinant proteins?
A. SDS are available and can be downloaded from the product page of the specific recombinant protein on our website.
Q. What Quality & Regulatory Support is offered for Shenandoah Recombinant Proteins?
A. We offer the following support for our Shenandoah Recombinant Proteins.
- Auditing of the production site, if necessary
- Detailed batch-specific test results on our Certificates of Analysis
Q. What Quality & Regulatory Support is offered for Shenandoah CTGrade GMP Recombinant Proteins?
A. We offer the following support for our Shenandoah CTGrade GMP Recombinant Proteins.
- Auditing of the production site, if necessary
- Detailed batch-specific test results on our Certificates of Analysis
- DMFs available on request
- Change notifications
Q. Do you offer free CTGrade GMP product samples?
A. Yes, fill out our Sample Request Form.
Q. If nothing is visible in the product vial, should I return it?
A. The vial contains only a few micrograms of product, which may not be visible. Many of the protein products are lyophilized with a low concentration buffer without carrier proteins (BSA, HSA, sucrose, mannitol, etc.). It is recommended to centrifuge the vial on tabletop spinner for up to 1 min before opening to ensure the product is not near the cap. Then, follow the reconstitution instructions found on the Certificate of Analysis (COA) for the product.
Q. Can I use a lyophilized recombinant protein product that was shipped at room temperature?
A. Yes. Lyophilized recombinant protein products are intended to be shipped at ambient temperature and are not compromised when exposed to normal shipping temperatures for extended periods of time (up to 5 days). Our products are routinely tested for bioactivity following exposure to ambient temperatures encountered during normal shipping conditions. Lyophilized proteins shipped at room temperature retain full activity. If you are having issues with the product/services, please contact Technical Support Services.
Q. What temperature should protein products be stored at?
A. After reconstitution and aliquoting, proteins should be stored at -20°C. Adding a carrier protein such as HSA or BSA will help protect the protein and prevent it from sticking to the wall of the vial. It is important to avoid repeated freeze thaw cycles as this can damage the protein and render it inactive.
Q. Is the standard bioassay used to confirm the activity level of the protein product a good indicator for the intended application?
A. A standard bioassay is used to confirm the activity level for the protein products. The proteins can be used in many different applications. Ultimately, the end user can determine which bioassay will work best for the intended application.
Q. Is specific activity (units/mg) the same as International Units (IU/mg)?
A. Specific activity (units/mg) is not the same as International Units (IU/mg). International Units are calculated using a validated assay where the protein in question is tested side-by-side with an Internal Standard (IS) set by the World Health Organization (WHO).
For those products that are not compared to IS, the data reported on our documents are considered "in-house-units" and are routinely run side-by-side with competitors from the recombinant protein market; hence, it is not desirable to compare to other assays directly. Even if the same cell line is used, there are still factors that will differ from lab to lab, and comparability of results can vary.
Q. How do I calculate Specific Activity?
A. The datasheet states the biological activity as an ED50. The ED50 is an expression of activity at 50% of its maximum response. You can calculate specific activity using the following formula: Specific Activity (units/mg) = 1 x 106 / ED50 (ng/ml).
Q. Do the protein products show cross-species activity?
A. Many human cytokines will have an effect in mouse cell lines, and many mouse proteins will show activity on human cells; however, species cross-reactivity must be investigated individually for each product.
