Recombinant Human Enteropeptidase/Enterokinase Protein, CF

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Citations (8)
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Recombinant Human Enteropeptidase/Enterokinase Protein, CF Summary

Product Specifications

>90%, by SDS-PAGE under reducing conditions and visualized by silver stain.
Endotoxin Level
<1.0 EU per 1 μg of the protein by the LAL method.
Measured by its ability to cleave a colorimetric peptide substrate, Z-Lys-SBzl. The specific activity is >10,000 pmol/min/µg, as measured under the described conditions.
Mouse myeloma cell line, NS0-derived human Enteropeptidase/Enterokinase protein
Leu41-His1019 & Ser118-His1019, with a C-terminal 9-His tag
Accession #
N-terminal Sequence
Leu41 & Ser118
Predicted Molecular Mass
110 kDa
150 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, NaCl and CaCl2.
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

  • Assay Buffer: 50 mM Tris, 0.15 M NaCl, 10 mM CaCl2, 0.05% Brij-35, pH 7.5 (TCNB)
  • Recombinant Human Enteropeptidase/Enterokinase (rhEnterokinase) (Catalog # 1585-SE)
  • Bacterial Thermolysin (Thermolysin) (Catalog # 3097-ZN)
  • 1,10 Phenanthroline (Sigma, Catalog # 320056), 0.6 M stock in DMSO
  • Substrate: thiobenzyl benzyloxycarbonyl-L-lysinate (Z-Lys-SBzl) (Bachem, Catalog # M-1300), 10 mM stock in DMSO
  • 96 well Clear Plate (Costar, Catalog #  92592)
  • 5,5’-dithio-bis(2-nitrobenzoic acid) (DTNB) (Sigma, Catalog # D-8130)
  • Plate Reader (Model: SpectraMax Plus by Molecular Devices) or equivalent
  1. Activate rhEnterokinase with Thermolysin.
    1. Dilute rhEnterokinase to 100 μg/mL in Assay Buffer.
    2. Dilute Thermolysin to 3.16 μg/mL in Assay buffer.
    3. Mix equal volumes of diluted rhEnterokinase and Thermolysin.
    4. Incubate at 37 °C for 30 minutes.
    5. Stop the reaction by adding an equal volume of 20 mM 1,10 Phenanthroline to the reaction tube.
  2. Dilute rhEnterokinase to 0.1 μg/mL in Assay Buffer.
  3. Dilute Substrate to 200 μM in Assay Buffer with 200 μM of DTNB.
  4. Load in a 96 well clear plate 50 μL of the diluted rhEnterokinase. For a Substrate Blank load 50 μL of the Assay Buffer.
  5. Start the reaction by adding 50 μL of the Substrate/DTNB mixture to wells.
  6. Read in kinetic mode for 5 minutes at an absorbance of 405 nm.
  7. Calculate specific activity:

     Specific Activity (pmol/min/µg) =

Adjusted Vmax* (OD/min) x well volume (L) x 1012 pmol/M
ext. coeff** (M-1cm-1) x path corr.*** (cm) x amount of enzyme (µg)

     *Adjusted for Substrate Blank

     **Using the extinction coefficient 13260 M-1cm-1

     ***Using the path correction 0.32 cm

     Note: the output of many spectrophotometers is in mOD

Per Well:
  • rhEnterokinase: 0.005 μg
  • DTNB: 100 μM
  • Substrate: 100 μM
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Background: Enteropeptidase/Enterokinase

EK initiates activation of pancreatic proteases by converting trypsinogen to trypsin, which in turn activates chymotrypsin, carboxypeptidases and elastases. Located in intestinal brush border, it is a disulfide bond linked dimer of the heavy and light chains, which are derived from the same single-chain precursor. The multidomain‑containing the heavy chain consists of a short cytoplamic tail, a transmembrane, a SEA, a SRCR, a MAM, two CUB and two LDL-receptor class A domains. The light chain contains the catalytic domain of trypsin-like serine proteases. The purified recombinant human EK corresponds to the single-chain form starting at the end of the transmembrane domain.

Entrez Gene IDs
5651 (Human)
Alternate Names
EC 3.4.21; EC; Enterokinase; Enteropeptidase; ENTK; ENTKenterokinase; MGC133046; protease, serine, 7 (enterokinase); PRSS7; PRSS7enteropeptidase; Serine protease 7; TMPRSS15; Transmembrane protease serine 15; transmembrane protease, serine 15

Citations for Recombinant Human Enteropeptidase/Enterokinase 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.

8 Citations: Showing 1 - 8
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  1. Preclinical testing of dabigatran in trypsin-dependent pancreatitis
    Authors: ZG Pesei, Z Jancsó, A Demcsák, BC Németh, S Vajda, M Sahin-Tóth
    JCI Insight, 2022-11-08;0(0):.
    Species: Human
    Sample Types: Recombinant Protein
    Applications: Bioassay
  2. Inactivation of mesotrypsin by chymotrypsin C prevents trypsin inhibitor degradation
    Authors: V Toldi, A Szabó, M Sahin-Tóth
    J. Biol. Chem., 2020-02-03;0(0):.
    Species: Human
    Sample Types: Whole Cell
    Applications: Enzyme Assay
  3. Natural single-nucleotide deletion in chymotrypsinogen C gene increases severity of secretagogue-induced pancreatitis in C57BL/6 mice
    Authors: A Geisz, Z Jancsó, BC Németh, E Hegyi, M Sahin-Tóth
    JCI Insight, 2019-06-18;5(0):.
    Species: Mouse
    Sample Types: Tissue Homogenates
    Applications: Bioassay
  4. Trypsinogen isoforms in the ferret pancreas
    Authors: E Hegyi, M Sahin-Tóth
    Sci Rep, 2018-10-10;8(1):15094.
  5. Zymogen activation confers thermodynamic stability on a key peptide bond and protects human cationic trypsin from degradation.
    Authors: Szabo A, Radisky E, Sahin-Toth M
    J Biol Chem, 2014-01-08;289(8):4753-61.
    Species: Human
    Sample Types: Protein
    Applications: Bioassay
  6. Autoactivation of mouse trypsinogens is regulated by chymotrypsin C via cleavage of the autolysis loop.
    Authors: Nemeth B, Wartmann T, Halangk W, Sahin-Toth M
    J Biol Chem, 2013-06-27;288(33):24049-62.
    Species: Mouse
    Sample Types: Tissue Homogenates
    Applications: Bioassay
  7. Interaction of protein C inhibitor with the type II transmembrane serine protease enteropeptidase.
    Authors: Prohaska TA, Wahlmuller FC, Furtmuller M, Geiger M
    PLoS ONE, 2012-06-19;7(6):e39262.
    Species: Human
    Sample Types: Recombinant Protein
    Applications: Enzyme Assay
  8. Chymotrypsin C (caldecrin) stimulates autoactivation of human cationic trypsinogen.
    Authors: Nemoda Z, Sahin-Toth M
    J. Biol. Chem., 2006-02-27;281(17):11879-86.
    Species: Human
    Sample Types: Pancreatic Fluid
    Applications: Enzyme Assay


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