Recombinant Proteins

Prior to performing bioassay validation and stability testing, we test each recombinant protein for product purity and quantification. In the table below you can find examples of the attributes tested, the test performed, and some acceptance criteria used to ensure that our customers are confident they are receiving the highest quality reagents.

Recombinant proteins were run in SDS-PAGE under either DTT-reducing or non-reducing conditions, as indicated, to confirm purity of the recombinant protein was >95%.

Recombinant proteins run on an LC-Agilent 6230 Time-of-Flight Mass Spectrometer. Deconvoluted mass spectrums shown with predicted and observed molecular weights indicated.

Each lot of our bioassay-validated recombinant proteins undergoes quality testing by functional assay to ensure the protein exhibits appropriate activity within a biologically relevant system. In this way, we ensure our proteins will perform within your experimental system. Some applications we test our proteins for include:

Learn more about how we use reference standards to calculate the specific activity of our proteins with Recombinant Protein Unit Conversions.

We offer the majority of our recombinant proteins in a convenient, ready-to-use liquid format, which have a comparable shelf-life to lyophilized proteins.

Advantages of Liquid Recombinant Proteins:

• Ready-to-use
• No buffer preparation
• No pH adjustment
• No filtration
• Reduced chance for contamination
• No risk of protein aggregation during reconstitution

We perform extensive stability testing to ensure that each of our proteins is stable in a liquid format when handled and stored properly. In most cases, our liquid format recombinant proteins exhibit superior in-use shelf life when compared with competitor lyophilized proteins. If extended storage is desired, our proteins typically possess comparable long-term stability to competitors when stored at -80°C.

Each recombinant protein released undergoes extensive stability testing to ensure product performance over the reagent’s entire shelf life.

Recombinant proteins were aliquoted in PBS pH 7.2 at 0.2 mg/ml. One aliquot was frozen and thawed four times (4x freeze/thaws), one was kept at RT, and one was kept at 37°C for one week. All samples were tested for bioactivity as compared to a control stored at 4°C.

We periodically retest our recombinant proteins at later time points and have shown that some recombinant proteins retain their activity even after 10 years in storage at -80°C.

Recombinant proteins stored at -80°C for 10 years were tested for bioactivity as compared to a fresh competitor  lyophilized protein.