FAQ

Below are some frequently asked questions of HumanZyme, Inc. If you cannot find the information you are looking for, or have further inquiries, please email support@humanzyme.com.

What is the ED50 Range and how is it compared to specific activity in units/mg?

We supply recombinant cytokines in µg (or mg) with a specific ED50 range rather than as specific activity in units per vial. The ED50 is defined as the cytokine concentration at which the bioassay activity is 50% of the maximum response. Bioassay is a measurement of biological response, such as cell proliferation assay, functional ELISA or an enzymatic assay, to a specific protein. Due to the variable nature of bioassays, the same cytokine preparation may not give you the same ED50 value at different occasions. In particular, any variation in a bioassay condition such as cell densities, age or even passage numbers may lead to variable results. Humanzyme report typical ED50 range on datasheet for a given cytokine. ED50 is accurate only when the cytokine dose-response curves are sigmoidal shape. The formula for converting the ED50 in ng/ml to specific activity in units/mg is:

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What are the advantages of HumanKine cytokines over E.Coli, CHO, and SF9 expressed proteins?

Recombinant humanKine cytokines and growth factors are expressed in an optimized, proprietary human cell line (HEK293). Proteins produced using our technology have native glycosylation, folding, disulfide linkages, and post-translational processing, so their biologic activity and stability are superior to proteins expressed in non-human systems. For more information, read our White Paper, Native Glycosylation Is Important For Biological Function and Activity of Recombinant Human Proteins.

How are HumanZyme products shipped?

HumanZyme cytokines and growth factors are shipped as lyophilized and carrier-free proteins. We recommend the vial is briefly centrifuged before opening, and follow product-specific instructions as described either on data sheet and/or certificate of analysis to reconstitute.

Is FGF-TS different that FGF-2?

FGF-TS is a thermostable variant of FGF-2 (FGF-basic) that has native biologic activity, with improved stability in culture media. Please see our White Paper, Thermostable FGF Basic Supports a 2-Day Feeding Schedule As Shown by Biochemical and Cell Culture Analysis.

Does HumanZyme offer sample sizes?

Please contact us at info@humanzyme.com to discuss your specific application and questions with us. Our products are configured in 10 µg, 50 µg and 1000 µg sizes and can be ordered over the phone with credit card or purchase order and shipped for next day arrival.

What is the expiration date of Humanzyme proteins, cytokines and growth factors?

Recombinant humanKine cytokines and growth factors are expressed in an optimized, proprietary human cell line (HEK293). Proteins produced using our technology have native glycosylation, folding, disulfide linkages, and post-translational processing, so their biologic activity and stability are superior to proteins expressed in non-human systems. For more information, read our White Paper, Native Glycosylation Is Important For Biological Function and Activity of Recombinant Human Proteins.

What are the advantages of HumanKine cytokines over E.Coli, CHO, and SF9 expressed proteins?

The expiration date of each protein is included on the Certificate of Analysis (CofA) shipped with the product, and is at least 1 year from date of ship.

In what applications can HumanZyme’s cytokines be used besides stem cell research and cell therapy?

HumanZyme proteins have been used for generation of anti-human cytokine antibodies, as they are the best representation of the cellular-expressed proteins available. View our website’s bibliography section where we have more than 125 citations for various applications listed.

What type of media does HumanZyme use for cytokine production with our expression system?

We use commercially available serum-free xeno-free medium.

Is your cell line available from ATCC?

HZ-293TS cells are deposited with ATCC under the Budapest Treaty (PTA-10165).

Can Humanzyme’s cytokines and growth factors be used for in vivo experiments?

HumanZyme’s cytokines and growth factors are Research Use Only (RUO) grade.

Does HumanZyme manufacture a GMP grade recombinant protein?

Please contact us for more information on GMP grade proteins. GMP proteins are produced under custom requirements and can be ordered by contacting us.