>95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
<1.0 EU per 1 μg of the protein by the LAL method.
28 kDa (pro) & 27 kDa (mature). 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.
Substrate: Boc-Val-Pro-Arg-AMC (Catalog # ES011), 100 mM stock in DMSO
F16 Black Maxisorp Plate (Nunc, Catalog # 475515)
Fluorescent Plate Reader (Model: SpectraMax Gemini EM by Molecular Devices) or equivalent
Dilute rhKLK13 to 100 µg/mL in Activation Buffer.
Dilute Lysyl-Endopeptidase to 0.8 µg/mL in Activation Buffer.
Activate rhKLK13 by adding 1 µL of 0.8 µg/mL Lysyl-Endopeptidase to 40 µL of 100 µg/mL rhKLK13 for a final concentration of 0.02 µg/mL for Lysyl-Endopeptidase.
Incubate at 37 °C for 30 minutes.
Dilute activated rhKLK13 to 2 ng/µL in Assay Buffer.
Dilute Substrate to 200 µM in Assay Buffer.
Load 50 µL of 2 ng/µL rhKLK13 in a plate, and start the reaction by adding 50 µL of 200 µM Substrate. Include a Substrate Blank containing 50 µL of Assay Buffer and 50 µL of 200 uM Substrate.
Read at excitation and emission wavelengths of 380 nm and 460 nm (top read), respectively in kinetic mode for 5 minutes.
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 (AMC) (Sigma, Catalog # A-9891).
rhKLK13: 0.1 µg
Substrate: 100 µM
This product is produced by and ships from R&D Systems, Inc., a Bio-Techne brand.
Alternate Names for Recombinant Human Kallikrein 13 Protein, CF
Kallikrein-like protein 4
kallikrein-related peptidase 13
KLKL4kallikrein-like gene 4
Human tissue Kallikrein 13 (hK13) is a member of the human tissue kallikrein family. The gene encoding for recombinant hK13 is termed KLK13 and it resides on chromosome 19q13.3-4 along with fourteen other members of the family. KLK13 spans about 8.7 kb genomic DNA and the longest transcript is 831 bp, encoding for a protein of 277 amino acids (1). Another five shorter splice variants have also been identified. They are specifically expressed in the testicular tissue and encode for five truncated forms of hK13 (2). Due to the aspartic acid residue in the substrate binding pocket, the enzymatic activity of hK13 is predicted be trypsin-like. It has been shown that recombinant hK13 produced in yeast can cleave synthetic peptides after the arginine residue and some extracellular matrix components (3). However, its exact physiological substrates and functions remain obscure. Despite the lack of knowledge on the physiological function of hK13, several studies have demonstrated that hK13 is implicated with cancer of the breast and ovary and it can serve as a favorable prognostic biomarker for these malignancies (4, 5). The purified, secreted recombinant hK13 is mainly the pro form. When activated by lysyl‑endopeptidase, it displays enzymatic activity towards a fluorogenic synthetic peptide described in the Activity Assay Protocol. This activity can be inhibited by recombinant human Serpin A5, E1 and F2 (Catalog # 1266-PI, 1786-PI, and 1470‑PI).
Yousef, G. M. et al. (2000) J. Biol. Chem. 275:11891.
Chang, A. et al. (2001) Anticancer Res. 21:3147.
Kapadia, C. et al. (2004) Biochem. Biophys. Res. Commun. 323:1084.
Chang, A. et al. (2002) Br. J. Cancer. 86:1457.
Scorilas, A. et al. (2004) J. Clin. Oncol. 22:678.
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