Recombinant Human Kallikrein 2 His-tag Protein, CF

Recombinant Human Kallikrein 2 His-tag (Catalog # 11691-SE) is measured by its ability to cleave the fluorogenic peptide substrate Pro-Phe-Arg-7-amido-4-methylcoumarin (PFR-AMC).

• Reactivity: Hu
• Applications: Enzyme Activity
• Format: Carrier-Free

Recombinant Human Kallikrein 2 His-tag Protein, CF Summary

• Additional Information: CHO expressed
• Details of Functionality: Measured by its ability to cleave a flourogenic peptide substrate Pro-Phe-Arg-7-amido-4-methylcoumarin (PFR-AMC). The specific activity is >250 pmol/min/μg, as measured under the described conditions.
• Source: Chinese Hamster Ovary cell line, CHO-derived human Kallikrein 2 protein
  Ile25-Pro261, with a C-terminal 10-His tag
• Accession #: P20151.1
• N-terminal Sequence: Ile25
• Protein/Peptide Type: Recombinant Enzymes
• Endotoxin Note: <0.10 EU per 1 μg of the protein by the LAL method.

Applications/Dilutions

• Dilutions:
  • Enzyme Activity
• Theoretical MW: 28 kDa.
  Disclaimer note: The observed molecular weight of the protein may vary from the listed predicted molecular weight due to post translational modifications, post translation cleavages, relative charges, and other experimental factors.
• SDS-PAGE: 22-32 kDa, under non-reducing conditions

Packaging, Storage & Formulations

• Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
  • 6 months from date of receipt, -20 to -70 °C as supplied.
  • 3 months, -20 to -70 °C under sterile conditions after opening.
• Buffer: Supplied as a 0.2 μm filtered solution in Sodium Citrate and NaCl.
• Assay Procedure:
  • Assay Buffer: 50 mM Tris, 150 mM NaCl, 10 mM CaCl₂, 0.05% (w/v) Brij-35, pH 7.5 (TCNB)
  • Recombinant Human Kallikrein 2 (rhKLK2) (Catalog # 11691-SE)
  • Substrate: Pro-Phe-Arg-AMC, 10 mM stock in DMSO
  • Black 96-well plate
  • Plate Reader with Fluorescence Read Capability
  1. Dilute rhKLK2 to 4 µg/mL in Assay Buffer.
  2. Dilute Substrate to 200 µM in Assay Buffer.
  3. In a plate, load 50 µL of 4 µg/mL rhKLK2, and start the reaction by adding 50 µL of the 200 µM Substrate. Include a Substrate Blank containing 50 µL of Assay Buffer and 50 µL of 200 µM Substrate.
  4. Read at excitation and emission wavelengths of 380 nm and 460 nm (top read), respectively, in kinetic mode for 5 minutes.
  5. Calculate specific activity:

  Specific Activity (pmol/min/µg) = (Adjusted Vmax* (RFU/min) x Conversion Factor** (pmol/RFU)) / (amount of enzyme (µg))

  *Adjusted for Substrate Blank
  **Derived using calibration standard 7-Amino, 4-Methyl Coumarin.
  Per Well:
  • rhKLK2: 0.2 µg
  • Substrate: 100 µM

Notes

This product is produced by and ships from R&D Systems, Inc., a Bio-Techne brand.

Alternate Names for Recombinant Human Kallikrein 2 His-tag Protein, CF

• EC 3.4.21
• EC 3.4.21.35
• glandular kallikrein 2
• Glandular kallikrein-1
• hGK-1
• hK2
• Kallikrein 2
• kallikrein 2, prostatic
• kallikrein-2
• kallikrein-related peptidase 2
• Klk1c2
• KLK2
• KLK2A2
• MGC12201
• Tissue kallikrein-2
• Ton

Background

Recombinant human Kallikrein 2 (KLK2) is also known as glandular kallikrein or the prostate-specific glandular kallikrein as it is structurally related to KLK3, the prostate-specific antigen (PSA). KLK2 is a secreted serine protease member of the tissue kallikrein subfamily family of the peptidase S1 family (1). It is highly expressed in the human prostate gland (2) and synthesized as a pre-proenzyme like other kallikriens. Removal of the propeptide occurs through cleavage by trypsin-like activity to activate the protein (1).  KLK2 also contains a catalytic domain with an extended 99 or kallikrein loop (3) and glycan that regulate its activity (4). KLK2 is highly specific for cleavage after arginine residues and is able to autoactivate and play a role in activation of KLK cascades (5). In addition, KLK2 has been reported to activate other key proteins including the urokinase-type plasminogen activator (6), IGFBPs (7), and IL10 (8). Its activity is highly regulated by activation cascades, endogenous inhibitors such as serpins protein C inhibitor, antichymotrypsin, and plasminogen activator inhibitor 1 (9-11), pH, and metal dependency (1). It is heavily implicated to play a role in prostate cancer and is attractive as a biomarker and therapeutic target (12-15). 

1. Prassas, I. et al. (2015) Nat. Rev. 14:183. 
2. Chapdelaine, P. et al. (1988) FEBS Lett. 236:205.
3. Skala, W. et al. (2014) J. Biol. Chem. 289:34267.
4. Guo, S. et al. (2016) J. Biol. Chem. 291:593. 
5. Yoon, H. et al. (2007) J. Biol. Chem. 282:31852.
6. Frenette, G. et al. (1997) Int. J. Cancer 71:897.
7. Emami, N. and E.P. Diamandis (2007) Mol. Oncol. 1:269.
8. Oliveira, J.R. et al. (2024) Biochemistry 63:2023.
9. Deperthes, D. et al. (1995) Biochim. Biophys. Acta 1245:311.
10. Grauer, L.S. et al. (1998) J. Androl. 19:407.
11. Mikolajczyk S.D. et al. (1999) Cancer Res. 59:3927.
12. Sardana, G. et al. (2008) Clin. Chem. 54:1951.
13. Shang, Z. et al. (2014) Tumor Biol. 35:1881.
14. Bonk, S. et al. (2020) Prostate 80:1097.
15. Zhang, J. and J.S. Chadha (2024) Cancers 16:3098.

Bioinformatics

• Uniprot:
  • P20151.1()