Overview of IGKC and Its Biological Role

The immunoglobulin kappa constant region protein, encoded by the IGKC gene, constitutes the constant domain of the immunoglobulin kappa (κ) light chain. Kappa light chains are one of the two types of immunoglobulin light chains (the other being lambda, λ) and pair non-covalently with immunoglobulin heavy chains to form functional antibody molecules. In humans, approximately 60% of antibodies carry kappa light chains, making IGKC one of the most physiologically abundant immunoglobulin components.

IGKC plays a structural role in stabilising the antibody architecture and contributes to antigen-binding geometry through its interaction with the variable kappa domain (IGKV). Beyond its canonical structural function, IGKC has been studied in the context of B-cell differentiation, plasma cell biology, and as a potential serum biomarker in certain disease states, including multiple myeloma and other B-cell malignancies.

Recombinant Human IGKC Protein (SKU: rp368287) provides researchers with an isolated, well-defined source of the IGKC domain for use in biochemical and cell-based assays where the native protein context is not required.

Product Specifications and Quality Attributes

Aladdin Scientific's Recombinant Human IGKC Protein (rp368287) is produced using recombinant protein expression technology to ensure batch-to-batch consistency and high purity. Researchers should consult the current product datasheet for the most up-to-date specifications, including:

• Protein identity: Human IGKC, kappa light-chain constant domain.
• Purity: Typically ≥90% as determined by SDS-PAGE and/or HPLC (verify exact value on datasheet).
• Endotoxin level: Low endotoxin preparations are recommended for cell-based functional assays; confirm specification on datasheet.
• Formulation: Supplied in a buffered solution optimised for stability; lyophilised options may be available (confirm with current datasheet).
• Molecular weight: Consistent with the calculated molecular weight of the IGKC domain; apparent MW on SDS-PAGE may vary under reducing vs. non-reducing conditions.

All lot-specific certificates of analysis (CoA) are available upon request from Aladdin Scientific customer service.

Recommended Protocols and Handling Guidelines

Follow these general guidelines when working with Recombinant Human IGKC Protein to ensure optimal experimental performance and protein integrity:

Reconstitution (if lyophilised)

1. Briefly centrifuge the vial before opening to collect contents at the bottom.
2. Reconstitute in sterile, ultra-pure water or the buffer recommended on the datasheet to the desired concentration.
3. Allow the vial to stand at room temperature for 5–10 minutes with gentle swirling; do not vortex.
4. Aliquot immediately to minimise freeze-thaw cycles and store aliquots at -80°C.

ELISA Application

1. Coat ELISA plates with the recombinant protein at the concentration recommended on the datasheet, overnight at 4°C.
2. Block with 1–3% BSA or 5% non-fat milk in PBS for 1 hour at room temperature.
3. Add primary antibody at appropriate dilution; incubate for 1–2 hours.
4. Wash, add HRP-conjugated secondary antibody, and develop with TMB substrate.

Western Blot

1. Resolve protein under reducing SDS-PAGE conditions.
2. Transfer to PVDF or nitrocellulose membrane.
3. Block and probe with anti-IGKC antibody at validated dilutions.
4. Detect with appropriate secondary antibody and imaging system.

Important: Optimal working concentrations should be determined empirically for each specific assay and instrument configuration.

Storage, Stability, and Shipping Conditions

Proper storage and handling are critical to maintaining the activity and integrity of Recombinant Human IGKC Protein:

• Short-term storage (up to 1 month): Store at 4°C in the supplied formulation buffer. Do not store at room temperature for extended periods.
• Long-term storage: Aliquot and store at -80°C. Avoid repeated freeze-thaw cycles, as these can lead to aggregation and loss of protein activity.
• Carrier protein addition: For very dilute working stocks, consider adding a carrier protein (e.g., 0.1% BSA) to prevent adsorption to tube surfaces.
• Shipping: The protein is shipped under conditions designed to maintain integrity during transit. Upon receipt, inspect the vial and store immediately under the recommended conditions.
• Shelf life: Refer to the expiry date on the product label and the CoA for the specific lot.

If any abnormality is observed upon receipt (e.g., visible aggregation, discolouration), contact Aladdin Scientific customer service immediately.

Research Applications and Relevant Use Cases

Recombinant Human IGKC Protein is suited to a range of immunological research contexts:

• Antibody biology studies: Use as a reference antigen or standard to investigate anti-kappa antibodies, light-chain interactions, and immunoglobulin assembly.
• Assay development and validation: Serves as a positive control or calibration standard in ELISA, Western blot, and immunoprecipitation assay development.
• Biomarker research: Supports studies investigating free light chains (FLC) and their clinical relevance in conditions such as multiple myeloma, systemic lupus erythematosus, and other B-cell dysregulation disorders.
• Protein–protein interaction studies: Can be used in pull-down assays or surface plasmon resonance (SPR) experiments to characterise interactions involving the kappa constant domain.
• Immunotherapy research: Relevant to studies examining CAR-T cell constructs or bispecific antibodies that target kappa light-chain-expressing cells.
• Educational and method development purposes: Suitable as a model recombinant protein for optimising expression, purification, or detection workflows in academic laboratory settings.

Researchers are encouraged to validate the protein's performance in their specific assay system prior to use in critical experiments.