Recombinant Human CD38 Protein, CF

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

• Assay Buffer: 50 mM MES, pH 6.5
• Recombinant Human CD38 (rhCD38) (Catalog # 2404-AC)
• Substrate: NGD+ (Sigma, Catalog # N-5131), 10 mM stock in deionized water
• F16 Black Maxisorp Plate (Nunc, Catalog # 475515)
• Fluorescent Plate Reader (Model: SpectraMax Gemini EM by Molecular Devices) or equivalent

1. Dilute rhCD38 to 2 ng/µL in Assay Buffer.
2. Dilute Substrate to 200 µM in Assay Buffer.
3. Load in plate, 50 µL of 2 ng/µL rhCD38, and start the reaction by adding 50 µL of 200 µM Substrate. Include a Substrate Blank containing 50 µL Assay Buffer and 50 µL of 200 µM Substrate.
4. Read at excitation and emission wavelengths of 300 nm and 410 nm (top read), respectively in kinetic mode for 5 minutes.
5. Calculate specific activity:

     *Adjusted for Substrate Blank
     **Derived using calibration standard cyclic GDP ribose (cGDPR).

• rhCD38: 0.1 µg
• Substrate: 100 µM