Recombinant Human Kallikrein 2 Protein: FAQs & Guide

Recombinant Human Kallikrein 2 Protein is a serine protease belonging to the kallikrein-related peptidase family, widely used in prostate cancer research, biomarker assay development, and proteolytic enzyme studies.

Protein Name

Recombinant Human Kallikrein 2 (KLK2)

Protein Family

Kallikrein-related peptidase / Serine protease

Primary Research Application

Prostate cancer biomarker research, enzyme activity assays, antibody development

Recommended Storage

-20°C or -80°C; avoid repeated freeze-thaw cycles

SKU

rp368593

Supplier Reference

absea#PQ-444

What Is Recombinant Human Kallikrein 2 Protein?

Recombinant Human Kallikrein 2 (KLK2) is a member of the human tissue kallikrein-related peptidase (KLK) gene family, which encodes secreted serine proteases. KLK2 is predominantly expressed in the prostate gland and is structurally related to Prostate-Specific Antigen (PSA/KLK3). The recombinant form is produced using heterologous expression systems to yield a purified, biologically active protein suitable for in vitro research applications. KLK2 cleaves substrates with trypsin-like specificity, preferring arginine at the P1 position. Its expression is androgen-regulated, making it a clinically relevant molecule in prostate cancer biology.

Handling, Reconstitution, and Storage of KLK2 Protein

Upon receipt, Recombinant Human Kallikrein 2 Protein should be briefly centrifuged before opening to ensure the material is collected at the bottom of the vial. If supplied lyophilized, reconstitute in sterile deionized water or the buffer recommended in the product datasheet to the appropriate concentration. Gently mix by pipetting; avoid vortexing to prevent protein denaturation. Aliquot the reconstituted protein into single-use volumes to minimize freeze-thaw cycles, which can reduce activity and increase aggregation. Store aliquots at -20°C for short-term use or -80°C for long-term storage. Carrier proteins such as BSA (0.1%) may be added to stabilize the protein at low concentrations. Always consult the specific product datasheet (absea#PQ-444) for lot-specific reconstitution volumes and storage recommendations.

Research Applications of Recombinant Human KLK2

Recombinant Human Kallikrein 2 Protein is used across a range of research applications:

• Prostate Cancer Biomarker Research: KLK2 serum levels are elevated in prostate cancer patients, making it a subject of clinical biomarker studies and immunoassay development.
• Enzyme Activity Assays: KLK2's trypsin-like serine protease activity is studied using fluorogenic or chromogenic peptide substrates.
• Antibody Development and Validation: As an antigen, recombinant KLK2 is used to generate and validate monoclonal and polyclonal antibodies for diagnostic and research use.
• Substrate Profiling: Used to identify and characterize physiological substrates relevant to seminal plasma biology and prostate physiology.
• Immunoassay Standards: High-purity recombinant KLK2 serves as a calibrator or positive control in ELISA and other immunoassay formats.

Purity, Quality, and Specifications

Recombinant proteins intended for research use are typically characterized by multiple quality attributes. For Recombinant Human Kallikrein 2 Protein (SKU: rp368593), researchers should refer to the Certificate of Analysis (CoA) and product datasheet (absea#PQ-444) for lot-specific data including:

• Purity: Typically assessed by SDS-PAGE and/or HPLC; research-grade recombinant proteins commonly achieve >90% purity.
• Biological Activity: Confirmed by enzymatic activity assay or functional ELISA where applicable.
• Endotoxin Level: Low endotoxin content is important for cell-based assays; check CoA for lot-specific values.
• Molecular Weight: Apparent molecular weight may differ from the theoretical value due to glycosylation or other post-translational modifications depending on the expression host.

Always request the CoA for the specific lot number received to verify these parameters before use.

Regulatory Status and Intended Use

Recombinant Human Kallikrein 2 Protein (rp368593) is supplied for research use only (RUO) and is not intended for diagnostic, therapeutic, or clinical use in humans or animals. It has not been evaluated by the FDA or equivalent regulatory agencies for such purposes. All experimental protocols must comply with applicable institutional biosafety and ethics guidelines. For any intended in vitro diagnostic (IVD) application, appropriate regulatory submissions and validations are required independently of this research reagent.

Frequently asked questions

What is the biological function of Human Kallikrein 2 (KLK2)?

KLK2 is a trypsin-like serine protease predominantly expressed in prostate epithelial cells under androgen regulation. It plays roles in semen liquefaction by cleaving seminal vesicle proteins and is implicated in prostate cancer progression through activation of pro-urokinase plasminogen activator and other substrates. Its elevated expression in prostate tissue and serum makes it a candidate biomarker for prostate cancer.

How should I reconstitute and store Recombinant Human KLK2 Protein?

If supplied as a lyophilized powder, reconstitute with sterile deionized water or the buffer specified in the product datasheet to the recommended concentration. Aliquot immediately after reconstitution to avoid repeated freeze-thaw cycles, and store at -20°C for short-term or -80°C for long-term storage. Adding a carrier protein such as 0.1% BSA can help stabilize the protein, especially at low concentrations. Always refer to the lot-specific CoA and datasheet (absea#PQ-444) for precise instructions.

What are the main research applications for Recombinant Human Kallikrein 2 Protein?

Recombinant Human KLK2 is used in prostate cancer biomarker research, enzyme kinetics and substrate profiling studies, immunoassay development and validation (including ELISA), and antibody generation. It also serves as a positive control or calibration standard in immunoassays detecting endogenous KLK2 in serum or tissue samples.

How does KLK2 differ from PSA (KLK3)?

KLK2 and KLK3 (PSA) are both androgen-regulated serine proteases expressed primarily in prostate tissue and are structurally homologous, sharing approximately 80% amino acid sequence identity. However, they differ in substrate specificity: KLK2 exhibits trypsin-like activity (cleaving after arginine/lysine), while KLK3 has chymotrypsin-like activity (cleaving after aromatic residues). KLK2 may offer complementary or superior specificity as a prostate cancer biomarker in certain clinical contexts.

Is Recombinant Human Kallikrein 2 Protein suitable for cell-based assays?

Recombinant Human KLK2 Protein can be used in cell-based assays, but researchers should verify the endotoxin level in the lot-specific CoA prior to use, as elevated endotoxin can confound cellular responses. Additionally, confirm that the protein is supplied in a buffer compatible with cell culture conditions. The product is for research use only and not validated for clinical or diagnostic applications.

References

1. Yousef GM, Diamandis EP. The new human tissue kallikrein gene family: structure, function, and association to disease. Endocr Rev. 2001;22(2):184-204.
2. Rittenhouse HG, Finlay JA, Mikolajczyk SD, Partin AW. Human Kallikrein 2 (hK2) and prostate-specific antigen (PSA): two closely related, but distinct, kallikreins in the prostate. Crit Rev Clin Lab Sci. 1998;35(4):275-368.
3. Kapadia C, Ghosh MC, Bhatt DL, et al. Human kallikrein 2 (KLK2) expression and substrate specificity. FEBS Lett. 2004;577(3):395-399.

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