Recombinant Human KLK9 Protein: FAQs & Technical Guide

Recombinant Human KLK9 Protein is a research-grade recombinant serine protease belonging to the kallikrein-related peptidase family, produced for use in biochemical assays, proteolysis studies, and biomarker research.

Product Name

Recombinant Human KLK9 Protein

SKU

rp368072

Protein Family

Kallikrein-related peptidase (KLK) serine protease family

Species

Human (Homo sapiens)

Protein Type

Recombinant serine endopeptidase

Intended Use

Research use only (RUO); not for diagnostic or therapeutic use

What Is KLK9 and Why Is It Important in Research?

KLK9 (Kallikrein-related peptidase 9) is a secreted serine protease and a member of the human tissue kallikrein family, which comprises 15 closely related serine proteases (KLK1–KLK15) encoded in a gene cluster on chromosome 19q13.4. KLK9 is expressed in a variety of tissues including the skin, brain, and reproductive organs, and has been implicated in diverse physiological processes such as extracellular matrix remodeling, skin desquamation, and neurological function.

From a translational perspective, KLK9 expression has been investigated as a potential biomarker in certain cancers, including ovarian and breast cancer, making recombinant KLK9 protein a valuable tool for assay development, antibody validation, and proteolytic activity studies. Researchers also use recombinant KLK9 to study substrate specificity and inhibitor screening within the broader context of the kallikrein protease cascade.

Expression System, Purity, and Formulation

Recombinant Human KLK9 Protein (rp368072) is produced using a recombinant expression system to ensure consistent quality and batch-to-batch reproducibility. The protein is typically purified by affinity chromatography and may include additional polishing steps (e.g., size-exclusion chromatography) to achieve high purity suitable for sensitive downstream assays.

Purity is generally assessed by SDS-PAGE and may be further confirmed by Western blot or HPLC. Researchers should consult the specific Certificate of Analysis (CoA) provided with each lot for confirmed purity percentage, endotoxin levels, and biological activity data. Endotoxin content is an important consideration especially for cell-based assays, and Aladdin Scientific recommends requesting lot-specific CoA data prior to experimental use.

Note: Specific purity percentage and endotoxin values are lot-dependent. Please refer to the product's CoA or contact Aladdin Scientific technical support for lot-specific specifications.

Storage, Stability, and Reconstitution Guidelines

Proper storage and handling of Recombinant Human KLK9 Protein are essential to maintain its structural integrity and biological activity. As a general guideline for recombinant proteins of this class:

• Short-term storage (up to 1 month): Store at 4 °C in the supplied formulation buffer.
• Long-term storage: Aliquot to avoid repeated freeze-thaw cycles and store at −20 °C or −80 °C. Repeated freeze-thaw cycles can lead to protein aggregation and loss of activity.
• Reconstitution: If supplied lyophilized, reconstitute with sterile deionized water or the recommended buffer as specified on the product datasheet. Allow the vial to equilibrate to room temperature before opening. Gently mix by pipetting; do not vortex.
• Carrier protein: Addition of a carrier protein such as 0.1–0.2% BSA is recommended when preparing dilute working solutions to minimize adsorption losses.

Important: Always refer to the product-specific datasheet and CoA for the most accurate and lot-confirmed storage and reconstitution instructions, as formulations may vary.

Typical Research Applications

Recombinant Human KLK9 Protein is suitable for a range of biochemical and cell biology research applications, including but not limited to:

• Enzyme activity assays: Characterization of KLK9 proteolytic activity using fluorogenic or chromogenic peptide substrates to determine kinetic parameters (Km, kcat) and inhibitor IC50 values.
• Antibody validation: Use as a positive control antigen in Western blot, ELISA, and immunoprecipitation experiments to confirm antibody specificity.
• Biomarker research: Development and calibration of immunoassays (e.g., ELISA) for measuring KLK9 levels in biological samples, particularly in oncology research.
• Protein-protein interaction studies: Investigation of KLK9 interactions with endogenous inhibitors (e.g., LEKTI/SPINK5) and other components of the kallikrein-kinin system.
• Substrate profiling: Identification of physiological substrates of KLK9 to elucidate its role in skin barrier function and cancer-related proteolytic cascades.

Ordering, Quality Assurance, and Regulatory Information

Recombinant Human KLK9 Protein is available from Aladdin Scientific under SKU rp368072. This product is intended for Research Use Only (RUO) and is not approved or intended for use in diagnostic, therapeutic, or clinical procedures.

Quality assurance: Each lot is manufactured under controlled conditions and is released with a Certificate of Analysis (CoA) documenting identity, purity, and activity testing results. Customers are encouraged to request the CoA for a specific lot before purchase or upon receipt.

Ordering: This product can be ordered directly through the Aladdin Scientific website or by contacting the sales team. For custom quantities, bulk orders, or specific formulation requests, please reach out to Aladdin Scientific customer support.

Returns and complaints: If the product does not meet specifications upon receipt, please contact Aladdin Scientific within the designated return window, retaining all original packaging and documentation to facilitate the claims process.

Frequently asked questions

What is Recombinant Human KLK9 Protein and what is its biological function?

Recombinant Human KLK9 Protein is a recombinantly expressed form of human kallikrein-related peptidase 9, a secreted serine endopeptidase belonging to the 15-member tissue kallikrein family encoded on chromosome 19q13.4. Biologically, KLK9 is involved in proteolytic cascades relevant to skin desquamation, extracellular matrix remodeling, and has been studied as a potential cancer biomarker, particularly in ovarian and breast cancer contexts.

How should I store and reconstitute Recombinant Human KLK9 Protein (rp368072)?

For short-term use (up to one month), store the protein at 4 °C in the supplied buffer. For long-term storage, prepare single-use aliquots and store at −20 °C or −80 °C to avoid activity loss from repeated freeze-thaw cycles. If the product is lyophilized, reconstitute with sterile deionized water or the buffer recommended on the datasheet, allow the vial to reach room temperature before opening, and mix gently by pipetting without vortexing. Always consult the lot-specific CoA and product datasheet for exact instructions.

What applications is Recombinant Human KLK9 Protein suitable for?

Recombinant Human KLK9 Protein (rp368072) is suitable for enzyme activity assays using fluorogenic or chromogenic substrates, antibody validation by Western blot or ELISA, immunoassay calibration for biomarker research, protein-protein interaction studies with endogenous inhibitors such as LEKTI, and substrate profiling studies. All applications are for research use only.

How do I confirm the purity and identity of my received lot of KLK9 protein?

Each lot of Recombinant Human KLK9 Protein is released with a Certificate of Analysis (CoA) that documents purity (typically assessed by SDS-PAGE), identity confirmation, endotoxin level, and activity data where applicable. Customers should request the CoA for their specific lot from Aladdin Scientific at the time of ordering or upon receipt. Additional in-house confirmation can be performed by running SDS-PAGE or Western blot using an anti-KLK9 antibody.

Is Recombinant Human KLK9 Protein (rp368072) suitable for in vivo or clinical use?

No. Recombinant Human KLK9 Protein (rp368072) is designated Research Use Only (RUO) and has not been evaluated or approved for diagnostic, therapeutic, or clinical applications. It must not be administered to humans or used in any clinical setting. Researchers intending cell-based assays should verify endotoxin levels from the CoA before use.

References

1. Lundwall A, Brattsand M. Kallikrein-related peptidases. Cell Mol Life Sci. 2008;65(13):2019–2038. doi:10.1007/s00018-008-8024-3
2. Diamandis EP, Yousef GM. Human tissue kallikreins: a family of new cancer biomarkers. Clin Chem. 2002;48(8):1198–1205. PMID:12142373
3. Borgono CA, Diamandis EP. The emerging roles of human tissue kallikreins in cancer. Nat Rev Cancer. 2004;4(11):876–890. doi:10.1038/nrc1474

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.