Recombinant Human SMAD3 Protein, N-His

What it means: Target is the identity of the recombinant protein you are purchasing. The target on this page is SMAD3.

How to interpret here: Use SMAD3 as your “match checkpoint” before ordering—confirm it aligns with your assay goal (antigen for antibody validation, standard for quantitation, binding partner for kinetics, or functional reagent). The sequence origin is Human; this matters when epitopes differ across species. The expressed construct is Asp220-Ser425—verify your epitope/domain is included. The expression system is E. coli (can affect folding and post‑translational modifications). Conjugate/tag status is N-His; plan capture/detection and tag controls accordingly. Purity is >90% as determined by SDS-PAGE.—important for low-background binding assays and standards. Molecular weight guidance 25.52 kDa helps you QC by SDS‑PAGE/Western. Physical form is Lyophilized; plan reconstitution/aliquoting based on this. Storage is Use a manual defrost freezer and avoid repeated freeze thaw cycles. Store at 2 to 8°C for frequent use. Store at -20 to -80°C for twelve months from the date of receipt.—use it to prevent degradation before your run. Reconstitution guidance is Reconstitute in sterile water for a stock solution. A copy of datasheet will be provided with the products, please refer to it for details.—follow it to preserve activity/solubility. Choose this when target + origin + construct + handling match your workflow; consider an alternative if you need full‑length vs fragment, a different origin, a different tag, or native PTMs.

Why it matters for buying:

• Biological relevance: Your results depend on whether the protein matches the pathway/epitope/interaction you intend to test.
• Reagent compatibility: Antibodies and ligands can be highly sensitive to construct boundaries, PTMs, and tags.
• Reproducibility: Clear target/construct details reduce “it binds in paper X but not in my hands” surprises.

Practical guidance:

• Confirm the binding site: If you know the epitope or functional domain, verify it overlaps the expressed region before ordering for a critical experiment.
• Plan a pilot: Test a small aliquot first to confirm binding/behavior in your buffer, surface chemistry, and detection method.
• Use controls: Include buffer-only and an unrelated protein control; add a tag-control when a conjugate/tag is present.
• Cell-based awareness: Endotoxin is listed as Please contact with the lab for this information.—important for immune readouts and stimulation assays.
• Buffer compatibility: Formulation is Lyophilized from a solution in PBS pH 7.4, 0.02% NLS, 1 mM EDTA, 4% Trehalose, 1% Mannitol.; confirm it won’t interfere with coating, conjugation, or coupling chemistries.

What to watch out for:

• PTM-dependent epitopes: Proteins expressed in bacteria often lack mammalian glycosylation—choose a host compatible with your epitope/function.
• Tag interference: Tags can create extra epitopes or steric effects; interpret binding with tag controls when needed.
• Construct mismatch: A fragment can be perfect for epitope mapping but may not behave like full‑length protein in functional assays.

What it means: Species is the organism the protein sequence is derived from (sequence origin). The value shown 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 that sequence. This listing is for SMAD3 from Human. The construct region Asp220-Ser425 helps confirm your epitope/domain is present. Note: species is different from expression system (this protein was produced in E. coli). If you plan cross‑species use, validate binding with ortholog panels and controls.

Why it matters for buying:

• Epitope differences: Small sequence changes across species can change binding and produce false negatives.
• Model relevance: Using the same species origin as your model reduces interpretation ambiguity.
• Cross-reactivity testing: Helps you intentionally test recognition across orthologs.

Practical guidance:

• Check your antibody datasheet: Compare immunogen/epitope information to the species listed here.
• Validate with dilutions: Test multiple concentrations to distinguish weak binding from non-specific background.
• Document details: Record species + region + tag/expression system in methods for reproducibility.

What to watch out for:

• Do not confuse with host: Species = sequence origin; expression system = production host.
• Isoforms/variants: If isoforms matter, verify the region/construct notes rather than relying on gene name alone.

What it means: Expression Region describes the exact construct that was expressed and purified (full‑length vs fragment, domains, and sometimes fusions). The value shown here is Asp220-Ser425.

How to interpret here: Treat Asp220-Ser425 as the “what you actually get” definition. For SMAD3, confirm this region includes your binding epitope or functional domain. If a conjugate/tag is present (N-His), confirm the region text doesn’t place it near your binding site. Pair this with expression system E. coli when native folding/PTMs are important. Use molecular weight guidance 25.52 kDa to QC the construct by SDS‑PAGE. Choose this when your epitope/domain is included; avoid if the region omits critical residues.

Why it matters for buying:

• Epitope inclusion: Many “no signal” outcomes come from ordering a fragment that lacks the epitope.
• Functional behavior: Full‑length and fragments can behave differently in activity assays and conformational binding.
• Immobilization/detection: Fusions/tags can change adsorption and apparent binding kinetics.

Practical guidance:

• Map domains first: If the assay depends on a domain (e.g., kinase domain, extracellular domain), confirm overlap before ordering.
• QC on arrival: Verify size and major species by SDS‑PAGE/Western for critical studies.
• Use construct-matched controls: When comparing variants, keep region and host consistent to reduce confounding.

What to watch out for:

• Missing signal peptides/TM regions: Many constructs omit these; that can change conformation.
• PTM-dependent sites: Fragments expressed in bacteria may not reproduce disulfide patterns or glycosylation.
• Assuming tag position: Do not assume N- vs C-terminal placement unless stated.

What it means: Expression System is the production host used to express the recombinant protein. The value shown 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 it typically lacks mammalian glycosylation and some native PTMs—important when epitopes are PTM‑ or conformation‑dependent. For SMAD3, choose an expression system compatible with your binding or functional requirements. Remember: species (Human) is sequence origin, not the production host. Endotoxin is listed as Please contact with the lab for this information.—important for cell-based assays. Follow storage guidance Use a manual defrost freezer and avoid repeated freeze thaw cycles. Store at 2 to 8°C for frequent use. Store at -20 to -80°C for twelve months from the date of receipt. to preserve structure after receipt/reconstitution.

Why it matters for buying:

• PTMs and conformation: Host affects glycosylation, disulfide formation, folding, and oligomerization.
• Assay background: Host-related impurities and endotoxin can confound sensitive or cell-based readouts.
• Comparability: Use the same host when comparing constructs to reduce confounding.

Practical guidance:

• Validate early: Run a small pilot under your exact buffer, immobilization, and detection conditions.
• Consider PTM sensitivity: If your reagent recognizes glycosylated/conformational epitopes, confirm the host can reproduce them.
• Use controls: Include an unrelated protein produced in the same host to identify host-driven background.

What to watch out for:

• Activity assumptions: Do not assume enzymatic or receptor activity unless explicitly validated.
• Aggregation risk: Some proteins aggregate depending on host and buffer—reconstitute gently and aliquot promptly.
• Cell stimulation: Suitability for cell stimulation requires additional validation beyond expression host.

What it means: Conjugate describes whether the protein includes a tag or labeling chemistry that changes capture/detection and sometimes solubility. The value shown here is N-His.

How to interpret here: Treat N-His as your capture/detection choice—select it based on how you plan to immobilize the protein, detect it, and control background. This listing is for SMAD3. The construct (Asp220-Ser425) helps you judge whether the tag may sit near your binding site. Pair this with expression system E. coli when native folding matters. Purity >90% as determined by SDS-PAGE. influences background; tag capture can sometimes reduce non‑specific adsorption versus passive coating. A His-tag enables Ni‑NTA capture and oriented immobilization; include a His‑tag control protein to detect tag-driven background.

Why it matters for buying:

• Workflow fit: Tags can dramatically simplify capture and improve immobilization reproducibility.
• Interpretation: Tags introduce additional epitopes and can change apparent binding kinetics; controls are essential.
• Downstream compatibility: Some downstream chemistries (coupling, labeling) are sensitive to buffer components and tags.

Practical guidance:

• Use tag controls: Include an unrelated protein with the same tag to identify tag-driven background.
• Optimize surface density: Overloading capture surfaces can cause steric crowding and reduce binding.
• Confirm tag location: If your binding site is near a terminus, tag placement can matter—check construct notes.
• Avoid chelators: EDTA can disrupt Ni‑NTA capture; keep buffers compatible.

What to watch out for:

• Tag interference: Tags can mask epitopes or introduce non‑specific binding; compare to tag‑free constructs if needed.
• Assuming cleavability: Do not assume tags are removable unless a protease site/protocol is provided.
• Surface artifacts: Tag capture can change orientation vs passive coating—interpret kinetics accordingly.

What it means: Form describes the physical state of the supplied protein (e.g., lyophilized powder vs liquid solution). The value shown here is Lyophilized.

How to interpret here: Use Lyophilized to plan how you will prepare the protein for your assay—reconstitution steps, concentration accuracy, aliquoting, and stability after thawing. Lyophilized proteins are shipped dry for stability, but your results depend on careful reconstitution (gentle mixing, correct buffer, and complete dissolution). Reconstitution guidance: Reconstitute in sterile water for a stock solution. A copy of datasheet will be provided with the products, please refer to it for details.. Formulation/buffer: Lyophilized from a solution in PBS pH 7.4, 0.02% NLS, 1 mM EDTA, 4% Trehalose, 1% Mannitol. (check compatibility with labeling/coupling and assay buffers). Storage: Use a manual defrost freezer and avoid repeated freeze thaw cycles. Store at 2 to 8°C for frequent use. Store at -20 to -80°C for twelve months from the date of receipt. (aliquot and minimize freeze–thaw). For SMAD3, a pilot dilution series after preparation helps confirm expected behavior.

Why it matters for buying:

• Stability and shipping risk: Lyophilized proteins often tolerate shipping better; liquids can be more temperature-sensitive.
• Concentration accuracy: Incomplete dissolution or pipetting viscous solutions can distort concentrations and assay signals.
• Downstream compatibility: Buffers/stabilizers in liquid formats can interfere with coating, conjugation, or coupling chemistries.

Practical guidance:

• Aliquot immediately: After reconstitution/thaw, aliquot into single-use portions to avoid repeated freeze–thaw.
• Mix gently: Avoid vigorous vortexing for sensitive proteins; gentle inversion or slow pipetting reduces aggregation risk.
• Verify solubility: If you see particulates, allow time to dissolve and consider centrifugation if compatible with your assay.
• Let it fully dissolve: After adding buffer, wait and mix gently until the solution is clear; concentration is unreliable if undissolved material remains.

What to watch out for:

• Freeze–thaw damage: Multiple cycles can reduce binding/activity and increase aggregation.
• Adsorption losses: Low-concentration proteins can stick to tubes; use low-bind plastics when possible.
• Buffer mismatch: Reconstituting in the wrong buffer can precipitate the protein or alter binding—follow recommended guidance.