Human S100A9 Protein

What it means: Target is the identity of the recombinant protein you are purchasing. The target on this page is S100A9.

How to interpret here: Use S100A9 as your “construct match” checkpoint—confirm it is the exact antigen/standard you need for your antibody validation, binding assay, or functional study. The sequence origin is Human (important for epitope differences across species). The expression system is E. coli, which can affect folding and post‑translational modifications. Tag status is No tag—use this to plan capture/immobilization (or to avoid tag interference). Purity is listed as > 97 % as determined by SDS-PAGE, which helps you judge background tolerance for your assay. Choose this when target + origin + construct details align with your experiment; consider another construct if you need full‑length protein, a different domain, a tag‑free format, or native PTMs.

Why it matters for buying:

• Specificity and binding: Closely related family members, isoforms, or fragments can change antibody/ligand binding.
• Assay validity: The same target produced in different systems or constructs can behave differently in ELISA coating, BLI/SPR, pull‑downs, or activity assays.
• Reproducibility: Documented construct details reduce surprises between batches and between publications.

Helpful selection notes for this listing:

• Accession cross‑check: S100A9 is linked to accession P06702 for sequence/domain verification when needed.
• Protein length: The recombinant human S100A9 consists of 113 amino acids and migrates with an apparent molecular mass of 13.2 kDa as estimated in SDS-PAGE under reducing conditions. (useful for confirming full‑length vs fragment).
• Synonyms: S100A9, 60B8AG, CAGB, CFAG, CGLB, L1AG, LIAG, MAC387.

Practical guidance:

• Confirm your binding site: Map your antibody epitope or functional domain to the expressed region before ordering for a critical assay.
• Plan a pilot: Test a small amount first to confirm binding/activity under your exact buffer and immobilization conditions.
• Use controls: Include buffer‑only and an unrelated protein control to detect non‑specific binding.
• Buffer awareness: Formulation is Lyophilized from sterile 150mM NaCl,20mM Tris , pH 8.0.—confirm compatibility with your downstream chemistry.
• Stability planning: Storage is Lyophilized Human S100A9 protein product should be stored desiccated below -20°C. Upon reconstitution, the protein should be stored at 4°C between 2-7 days and for future use below -20°C. For long term storage it is recommended to add a carrier protein (0.1% HSA or BSA). Please prevent freeze-thaw cycles.—aliquot to avoid repeated freeze–thaw.

What to watch out for:

• PTM‑dependent epitopes: Some antibodies/ligands require glycosylation or native folding—confirm the expression system supports what you need.
• Tag interference: Tags can introduce extra epitopes or steric effects; use tag‑controls when interpreting binding data.
• Construct mismatch: A protein fragment can be excellent for epitope mapping but may not reproduce full‑length functional behavior.

What it means: Species is the organism the protein sequence is derived from (sequence origin). The species listed here is Human.

How to interpret here: Use Human to decide whether the protein matches the biology you’re studying and whether your antibody/ligand is expected to recognize this sequence. This listing is for S100A9 from Human. Remember: species is not the same as expression system (this protein was produced in E. coli). Choose this when your reagents and study design align to this origin; validate cross‑species if you plan to use it as a surrogate for another organism.

Why it matters for buying:

• Epitope differences: Small sequence changes across species can change antibody binding (including false negatives).
• Cross‑reactivity studies: If you’re testing cross‑species recognition, this chip tells you what you’re actually testing.
• Translation: For human studies, using human‑origin protein reduces ambiguity when interpreting binding and standards.

Practical guidance:

• Check your antibody datasheet: Compare immunogen/epitope information to the species listed here.
• Use ortholog panels: For cross‑reactivity, test multiple ortholog proteins with the same protocol and controls.
• Document construct details: Record species + region + expression system in methods for reproducibility.

What to watch out for:

• Do not confuse with host: Species is sequence origin; expression system describes the production host.
• Variant/isoform differences: If isoforms matter, confirm the accession/region in the datasheet.

What it means: Expression System is the production host used to express the recombinant protein. The expression system listed here is E. coli.

How to interpret here: Use E. coli to predict whether the protein will be “native‑like” for your application (folding, disulfides, and post‑translational modifications). E. coli expression is fast and common, but typically lacks mammalian glycosylation and some native PTMs—important if your antibody/ligand is PTM‑ or conformation‑dependent. For S100A9, choose an expression system compatible with your binding or functional requirements. Note that species (Human) is sequence origin, not the production host. Pair host choice with formulation (Lyophilized from sterile 150mM NaCl,20mM Tris , pH 8.0.) when planning downstream chemistry and stability. Follow the listed storage conditions (Lyophilized Human S100A9 protein product should be stored desiccated below -20°C. Upon reconstitution, the protein should be stored at 4°C between 2-7 days and for future use below -20°C. For long term storage it is recommended to add a carrier protein (0.1% HSA or BSA). Please prevent freeze-thaw cycles.) to preserve structure after reconstitution. Choose this when host limitations do not conflict with your assay; consider mammalian/insect expression when native PTMs or complex folding are critical.

Why it matters for buying:

• PTMs and conformation: Host affects glycosylation, disulfide bonding, folding, and oligomerization—key for many epitopes and receptors.
• Assay background: Host-related impurities can influence low-signal assays; bacterial systems may also introduce endotoxin relevant to cell-based work.
• Comparability: Use the same expression system when comparing binding across constructs to reduce confounding.

Practical guidance:

• Validate early: Run a small pilot with your antibody/ligand under your exact buffer and immobilization conditions.
• Consider PTM sensitivity: If your reagents recognize glycosylated or conformational epitopes, verify the host can reproduce them.
• Use controls: Include an unrelated protein produced in the same host to help interpret host-driven background.

What to watch out for:

• “Works in cells” assumptions: A recombinant protein may be suitable for binding assays but not necessarily for cell stimulation without additional validation.
• Aggregation risk: Some proteins aggregate depending on host and buffer—reconstitute gently and avoid repeated freeze–thaw.
• Activity expectations: Do not assume enzymatic or receptor activity unless explicitly validated in the datasheet.

What it means: Conjugate/Tag describes whether the protein includes an affinity or fusion tag. The tag value shown here is No tag.

How to interpret here: Use No tag to decide how you will capture, detect, purify, or immobilize the protein in your workflow. Tag‑free proteins can reduce assay interference and better mimic native termini, but you lose tag-based capture convenience. For S100A9, consider whether tag placement could overlap the functional/binding region. Purity (> 97 % as determined by SDS-PAGE) influences background; tag-based capture can sometimes reduce non-specific adsorption compared to passive coating. Choose this when the tag strategy supports your downstream method; choose tag‑free when native-like behavior is more important than convenience.

Why it matters for buying:

• Workflow integration: Tags enable affinity capture, standardized immobilization, and sometimes simpler QC.
• Assay interference: Tags can drive non‑specific binding or mask epitopes; controls are essential in sensitive assays.
• Comparability: Comparing tagged vs tag‑free proteins can change apparent binding/kinetics even with the same target.

Practical guidance:

• Control for tag: Include an unrelated protein with the same tag, or a tag-only control, to detect tag-driven background.
• Prefer oriented capture when possible: Tag capture can improve reproducibility versus random passive adsorption on plates/surfaces.
• Confirm tag location: N- vs C-terminal tags can influence different binding sites—check the datasheet if critical.

What to watch out for:

• Anti-tag cross-reactivity: If you use anti-tag antibodies, ensure they do not bind other assay components.
• Surface overloading: Too much protein on a capture surface can cause steric crowding and reduced apparent binding.
• Tag removability assumptions: Do not assume the tag is cleavable unless stated.

What it means: Purity indicates how clean the preparation is (often estimated by SDS‑PAGE). The purity statement shown here is > 97 % as determined by SDS-PAGE.

How to interpret here: Use > 97 % as determined by SDS-PAGE to judge whether the protein is suitable for your assay’s background tolerance and sensitivity. For S100A9, higher purity is especially helpful when using the protein as a quantitative standard or in low-signal binding experiments. Tag status (No tag) can influence background; tag‑capture approaches may reduce non‑specific adsorption compared with passive coating. Also consider formulation (Lyophilized from sterile 150mM NaCl,20mM Tris , pH 8.0.), which can influence non‑specific binding and stability. Follow storage guidance (Lyophilized Human S100A9 protein product should be stored desiccated below -20°C. Upon reconstitution, the protein should be stored at 4°C between 2-7 days and for future use below -20°C. For long term storage it is recommended to add a carrier protein (0.1% HSA or BSA). Please prevent freeze-thaw cycles.) to preserve integrity after reconstitution. Shipping (Gel pack with blue ice.) can affect thermal exposure; inspect and aliquot promptly after receipt. Choose this when the stated purity meets your use-case; consider higher purity/extra QC for quantitative standards, kinetics, or cell-based assays.

Why it matters for buying:

• Lower background: Impurities can increase non‑specific binding in ELISA coating and surface binding assays.
• Reproducibility: Cleaner preparations generally reduce variability across runs and lots.
• Downstream compatibility: Contaminants can confound functional assays or create false binding signals.

Practical guidance:

• Match purity to application: Screening may tolerate lower purity; quantitative standards and kinetics benefit from cleaner prep.
• QC on arrival: For critical work, confirm band size and major species by SDS‑PAGE/Western.
• Use controls: Include buffer and unrelated protein controls to interpret background binding.

What to watch out for:

• Purity method differences: SDS‑PAGE estimates do not guarantee a single molecular species (aggregates/fragments may exist).
• Aggregation: Purity does not report aggregation—reconstitute gently and inspect solubility if binding looks inconsistent.
• Cell-based sensitivity: For cell assays, confirm endotoxin/host contaminants if unexpected responses occur.