Recombinant IL-5,Rat

What it means: Escherichia coli — this protein was produced using the Escherichia coli expression system, determining its glycosylation profile, folding, and application suitability.

Why it matters:

• E. coli systems provide high-yield, non-glycosylated protein ideal for biochemical assays; CHO and HEK293 systems support mammalian-like glycosylation for receptor-binding and cell-based studies.
• Expression system selection affects protein folding, disulfide bond formation, and post-translational modifications that may influence bioactivity and immunogenicity.

How to interpret here: This protein was expressed in Escherichia coli. Verify this matches your application requirements before ordering, particularly for cell stimulation or receptor-binding experiments.

What it means: > 95% by SDS-PAGE analysis. — purity was assessed by SDS-PAGE and HPLC to confirm the target protein comprises the stated proportion of the preparation.

Why it matters:

• High purity (>95%) minimises contaminant interference in sensitive assays including cell proliferation/survival bioassays, ELISA, SPR/BLI, and receptor-binding experiments.
• Consistent purity ensures reliable dose-response relationships in functional studies.

How to interpret here: > 95% by SDS-PAGE analysis. meets the release specification confirmed by lot-specific SDS-PAGE on the Certificate of Analysis. Contact technical support if >99% purity is required for biophysical measurements.

What it means: ED50 < 0.4 ng — this protein has been validated for functional bioactivity using a standardised cell-based assay, confirming it is correctly folded and biologically active.

Why it matters:

• The ED50 (effective dose for 50% maximal response) provides a quantitative measure of potency for designing dose-response experiments and comparing lot-to-lot consistency.
• Bioactivity confirmation distinguishes this protein from non-functional reference-only grades, making it suitable for cell stimulation, pathway activation, and functional assay studies.

How to interpret here: The stated ED50 < 0.4 ng was determined under specific assay conditions (see Certificate of Analysis). Optimal working concentrations may vary depending on your cell type, assay format, and culture conditions.

What it means: LAL-tested, < 0.2 EU/μg, determined by LAL method. — endotoxin content was quantified using the Limulus Amebocyte Lysate (LAL) chromogenic method.

Why it matters:

• Endotoxin activates NF-κB and TLR4 signalling in immune and endothelial cells, causing artefactual cytokine production that can completely mask the true biological activity of the protein.
• Low endotoxin (<0.2 EU/µg or <1 EU/mg) is the standard for cell-based stimulation assays and in vivo applications.

How to interpret here: This product meets the endotoxin specification as confirmed on the Certificate of Analysis. Suitable for cell culture, primary cell stimulation, and assays sensitive to innate immune pathway activation.

What it means: 26.0 kDa, observed by non-reducing SDS-PAGE. — the molecular weight was determined by SDS-PAGE under reducing or non-reducing conditions as indicated.

Why it matters:

• Apparent molecular weight on SDS-PAGE may differ from the theoretical mass due to glycosylation, signal peptide cleavage, or anomalous SDS binding of some proteins.
• The observed MW confirms correct processing and is used to validate protein identity in your experimental samples by co-running with this standard.

How to interpret here: The reported 26.0 kDa, observed by non-reducing SDS-P is the observed molecular weight under the stated conditions. Confirm this matches the band position expected in your Western Blot or SDS-PAGE analysis.

What it means: Lyophilized (freeze-dried) powder — the protein was formulated, filtered, and lyophilized for optimal stability during shipping and long-term storage.

Why it matters:

• Lyophilization extends shelf life to 6–12 months at −80°C by removing water and preventing hydrolytic degradation, aggregation, and loss of bioactivity.
• Lyophilized format allows flexible reconstitution at the concentration required for your assay, without the freeze-thaw sensitivity of liquid protein stocks.

How to interpret here: Reconstitute as directed on the Certificate of Analysis (typically in sterile ddH₂O or PBS at 100 µg/mL). Prepare single-use working aliquots and store at −80°C to preserve bioactivity.