Recombinant Human Cathepsin E Protein, CF

• 6 months from date of receipt, -20 to -70 °C as supplied.
• 3 months, -20 to -70 °C under sterile conditions after reconstitution.

• Assay Buffer: 0.1 M NaOAc, 0.5 M NaCl, pH 3.5
• Recombinant Human Cathepsin E (rhCathepsin E) (Catalog # 1294-AS)
• Fluorogenic Peptide Substrate I: MCA-Pro-Leu-Gly-Leu-DPA-Ala-Arg-NH₂ (Catalog # ES001)
• F16 Black Maxisorp Plate (Nunc, Catalog # 475515)
• Fluorescent Plate Reader (Model: SpectraMax Gemini EM by Molecular Devices) or equivalent

1. Dilute rhCathepsin E to 1.0 µg/mL in Assay Buffer.
2. Incubate at room temperature for 30 minutes (required to fully activate).
3. Dilute activated rhCathepsin E to 0.2 ng/µL in Assay Buffer.
4. Dilute Substrate to 40 µM in Assay Buffer.
5. Load 50 µL of the 0.2 ng/µL rhCathepsin E into a black well plate, and start the reaction by adding 50 µL of 40 µM Substrate. Include a Substrate Blank containing 50 µL Assay Buffer and 50 µL of 40 µM Substrate without any rhCathepsin E.
6. Read at excitation and emission wavelengths of 320 nm and 405 nm (top read), respectively, in kinetic mode for 5 minutes.
7. Calculate specific activity:

     *Adjusted for Substrate Blank
     **Derived using calibration standard MCA-Pro-Leu-OH (Bachem, Catalog # M-1975).

• rhCathepsin E: 0.01 µg
• Substrate: 20 µM