Recombinant Human Chymotrypsin C/CTRC Protein, CF

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Recombinant Human Chymotrypsin C/CTRC Protein, CF Summary

Product Specifications

>95%, by SDS-PAGE under reducing conditions and visualized by Colloidal Coomassie® Blue stain at 5 μg per lane
Endotoxin Level
<1.0 EU per 1 μg of the protein by the LAL method.
Measured by its ability to cleave the fluorogenic peptide substrate, SUC-Ala-Ala-Pro-Phe-AMC. The specific activity is >400 pmol/min/μg, as measured under the described conditions.
Chinese Hamster Ovary cell line, CHO-derived human Chymotrypsin C/CTRC protein
Met1-Leu268, with a C-terminal 6-His tag
Accession #
N-terminal Sequence
Predicted Molecular Mass
28.8 kDa
33-40 kDa, reducing conditions

Product Datasheets

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Carrier Free

What does CF mean?

CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our recombinant proteins. Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant protein to be stored at a more dilute concentration. The carrier free version does not contain BSA.

What formulation is right for me?

In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or as an ELISA standard. In contrast, the carrier free protein is recommended for applications, in which the presence of BSA could interfere.


Formulation Supplied as a 0.2 μm filtered solution in Tris and NaCl.
Shipping The product is shipped with polar packs. Upon receipt, store it immediately at the temperature recommended below.
Stability & 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.

Assay Procedure

  • Activation Buffer: 50 mM Tris, 10 mM CaCl2, 150 mM NaCl, pH 7.5 (TCN)
  • Assay Buffer: 25 mM Tris, 0.5 mM CaCl2, pH 8.0
  • Recombinant Human Chymotrypsin C/CTRC (rhCTRC) (Catalog # 6907-SE)
  • Trypsin (Sigma, Catalog # T1426)
  • Recombinant Human Serpin F2/ alpha 2‑Antiplasmin (rhSerpin F2) (Catalog # 1470-PI) (optional)
  • Substrate: Suc-AAPF-AMC (Bachem, Catalog # I-1465), 10 mM stock in DMSO
  • F16 Black Maxisorp Plate (Nunc, Catalog # 475515)
  • Fluorescent Plate Reader (Model: SpectraMax Gemini EM by Molecular Devices) or equivalent
  1. Dilute rhCTRC to 200 µg/mL in Activation Buffer.
  2. Dilute Trypsin to 0.4 µg/mL in Activation Buffer.
  3. Combine equal volumes of 200 µg/mL rhCTRC and 0.4 µg/mL Trypsin.
  4. Incubate at 37 °C for 1 hour.
  5. Optional: Stop Trypsin activity by adding rhSerpin F2 to a final concentration of 4 µg/mL.
  6. Dilute rhCTRC to 1 ng/µL in Assay Buffer.
  7. Dilute Substrate to 200 µM in Assay Buffer.
  8. Load into a black well plate 50 µL of the 1 ng/µL rhCTRC and start the reaction by adding 50 µL of 200 µM Substrate. For a Substrate Blank, load Assay Buffer in place of the rhCTRC.
  9. Read at excitation and emission wavelengths of 380 nm and 460 nm (top read), respectively, in kinetic mode for 5 minutes.
  10. 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 # A9891).

Per Well:
  • rhCTRC: 0.050 µg
  • Substrate: 100 µM
Reconstitution Calculator

Reconstitution Calculator

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Background: Chymotrypsin C/CTRC

Chymotrypsin C (CTRC), also known as caldecrin, is a serine protease and a member of the peptidase S1 family. The CTRC gene encodes a serum calcium‑decreasing factor that has chymotrypsin-like protease activity (1). CTRC has broad substrate specificity, but prefers to cleave on the carboxyl side of hydrophobic residues. The enzyme is expressed primarily in the pancreas, and is secreted into the digestive tract. CTRC is a key regulator of activation and degradation of cationic trypsinogen (2, 3). The inappropriate activation of cationic trypsinogen can contribute to the development of pancreatitis (2, 3). CTRC inhibits osteoclast differentiation by suppression of NFATc1 function by a mechanism independent of its proteolytic activity (4).

  1. Tomomura, A. et al. (1995) J. Biol. Chem. 270:30315.
  2. Szmola, R. and M. Sahin-Toth (2007) Proc. Natl. Acad. Sci. USA 104:11227.
  3. Nemoda, Z. and M. Sahin-Toth (2006) J. Biol. Chem. 281:11879.
  4. Hasegawa, H. et al. (2010) J. Biol. Chem. 285:25448.

Entrez Gene IDs
11330 (Human); 76701 (Mouse)
Alternate Names
Caldecrin; chymotrypsin C (caldecrin); Chymotrypsin C; chymotrypsin-C; CLCR; CLCRserum calcium decreasing factor; CTRC; EC 3.4.21; EC; ELA4; elastase 4; Elastase IV

Product Specific Notices

Coomassie is a registered trademark of Imperial Chemical Industries Ltd.

Citation for Recombinant Human Chymotrypsin C/CTRC Protein, CF

R&D Systems personnel manually curate a database that contains references using R&D Systems products. The data collected includes not only links to publications in PubMed, but also provides information about sample types, species, and experimental conditions.

1 Citation: Showing 1 - 1

  1. Inhibition of Human Kallikrein 5 Protease by Triterpenoids from Natural Sources
    Authors: Y Matsubara, T Matsumoto, J Koseki, A Kaneko, S Aiba, K Yamasaki
    Molecules, 2017-10-27;22(11):.
    Species: Human
    Sample Types: Recombinant Protein
    Applications: Bioassay


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