1. Is Healthgen a trader or a manufacturer?
2. Had the viruses tested for the final product?
A. None of any recombinant proteins are tested for viruses, especially from the plant source. FDA had no special request on the recombinant proteins, because FDA doesn’t worry about virus risks from recombinant proteins. Our recombinant HSA is derived from plant - rice, which Chinese people have eating thousands of years. And plant-derived eliminates the contamination risks of animal-derived components, including viral, prions/BSE, and other infectious agents. What's more, many experts consider the products from plants to be safer than those from mammalian sources, as small amounts of pathogenic material from a host animal could mix with and contaminate the new compound. No known plant viruses have infected humans, unlike animal pathogens. So the virus is not a problem for our recombinant HSA. That's why FDA don’t worry that much.
3. Any traces of the host organism in the final product?
A. According to the specification, the host cell DNA is not more than 0.5ng/g, the host cell protein is not more than 5.0μg/g.
4. The proper concentration of OsrHSA used in cell culture media?
A. 0.5g/L to 5g/L is the recommended concentration for cells culture media. It also depends on the types of cell clines.
5. What’s the highest concentration of HSA that can be soluble in the solution?
A. Our rHSA can be highest soluble 100% in 75% solution.
6. What’s the storage time / shelf life of our rHSA (lyophilized powder and solution)? Whether the protein is stable at room temperature?
A: The protein is stable at room temperature about two weeks but can’t keep too long.
The shelf life of rHSA lyophilized powder is 2 years at 2-8℃.iqud form could be stored for at least 2.5years at 2-8℃
7. Do we use the octanote during the production of rHSA?
A. Our final product contains 0.16mM octanote, and we also provide fatty acid-free rHSA.
8. What’s standard does your product comply? The Novozymes product complies to the USP-NF standards. Do you have DMF for our rHSA?
The USDMF No. is xxxxx. And OsrHSA is compliance most of the USP-NF and CP, due to its unique expression platform for recombinant proteins.
9. How does your rHSA compare with pHSA in terms of activity?
A. OsrHSA is purified by conventional chramotogarphy technologies without any organic agents treatments, the activity of OsrHSA can be well reserved. The most important biological activity of albumin is its outstanding binding capacity for various ligands such as hormones, lipids, ions and other molecules. OsrHSA showed the same affinities for ligands as pHSA in vitro according to our tests. OsrHSA also promotes cell growth as pHSA does. So it can be concluded OsrHSA has the same biological activity as pHSA.
10. If this product contains any chemically glycated protein (possibly from plant sugars)? A customer needs an albumin (or other protein) that does not contain any glycated or glycosylated protein (cannot have any protein with surface sugars). Can you confirm that OsrHSA does not have any surface sugars?
A. Glycosylation is a post-translational modification of proteins, sugars were added to specific sequences of proteins by enzymes. The specific sequence is NXS/T (X can be any kind of amino acid except proline). However, human serum albumin has no such a sequence. The enzymatic glycosylation does not occured in OsrHSA. The chemical glycation (or non-enzymatic glycosylation) is often added to amino of proteins. This modification may happen in process of protein. We think it may not exist according to our previous structural and sequences analysis, and we will further confirm it in next days.
Human albumin is a single peptide chain with one free sulfhydryl group on residue # 34 and 17 intrachain disulfide bonds.
Mass Spec Analysis of various commercial preparations indicates the presence of several post-translational modifications. Native human serum albumin is not a glycoprotein in the traditional sense. However, several genetic variants exist that may undergo enzymatic N-& O-glycosylation. Upon circulation in plasma, albumin often becomes glucosylated on εamine groups of lysine and possibly arginine residues. This is the result of the non-enzymatic spontaneous Maillard Reaction between the carbonyl group of the open ring form of glucose, present in small amounts in plasma, forming a Schiff base with the exposed primary amines of circulating proteins such as albumin, insulin and hemoglobin. Sigma has also observed various degrees of glucosylation in recombinant preparations. Cysteinylation is also present in native and recombinant preparations.
11. If OsrHSA has been tested for viruses (to show that it is negative)? Has it been tested for traces of rice cells?
1) About the Virus testing:
We have tested OsrHSA for virus and it is negative. OsrHSA can avoid any risk of viral contamination theoretically. Because our OsrHSA is a plant derived recombinant HSA. No animal components were introduced in the manufacturing process. Such a production process should eliminate safety concerns of animal-derived components including viruses, prions/BSE, and others. We also have validated it.
2) About the trace of the rice cells in OsrHSA:
We are proceeding the relative tests now. Since this is a key issue for safety, and we are planning to make our final product into the potential injection application, we need to have every safety issue clear before our application to clinical Phase I. The data of the trace of the host cell' DNA may will be available and later will be the trace of the host cell protein. In the expression of rHSA rice endosperm cells，the cells goes through the PCD（programed cell death）,that means no available cells in the raw material.
12. What will be the benefit when HSA is used for cells storage as cryopreservation reagent?
A: Our OsrHSA can reduce the usage of DMSO which is an ingredient in the cryoprotectant. DMSO can damage the cell but also can keep freezing. OsrHSA can also maintain osmotic pressure between cells.
13. How do you recommend to resuspend the rHSA powder: by using water? saline? other?
A: PB buffer is recommended to resuspend the rHSA powder.
14.Do you use any virus for the transfection in the manufacturing process of recombinant proteins?
A: No, we don't.
The target gene was introduced to plant by agrobacterium in the transfection, no virus weused in the expression or purification, and the manufacture process is also under GMP management. So, the product is animal-free, virus-free, and with a better biosafety.
15. What is the suggested concentration of IGF-1, IGF-1 LR3, FGF, EGF,KGF,Lysozyme in a face cream or serum?
0.01%-0.1% , 0.001%-0.01%, 0.01%, 0.005%-0.05%, 0.001-0.01%, 1%-2% at most.