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Recombinant Human Cystatin D Protein, CF

Catalog # 1202-PI | R&D Systems, Inc. a Bio-Techne Brand
Catalog #
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Key Product Details



Accession #




Inhibition Activity

Product Specifications


Mouse myeloma cell line, NS0-derived human Cystatin D protein
Thr29-Val142, with a C-terminal 10-His tag


>95%, 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.

N-terminal Sequence Analysis


Predicted Molecular Mass

15 kDa


15 kDa, reducing conditions


Measured by its ability to inhibit papain cleavage of a fluorogenic peptide substrate Z-FR-AMC (Catalog # ES009).
The IC50 value is <8 nM, under the described conditions.

Formulation, Preparation and Storage

Formulation Lyophilized from a 0.2 μm filtered solution in MES and NaCl.
Reconstitution Reconstitute at 100 μg/mL in sterile 50 mM Tris, pH 7.0.
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 reconstitution.

Background: Cystatin D

Cystatin D is a member of family 2 of the cystatin superfamily (1). In contrast to other members of family 2, Cystatin D has restricted tissue distribution and has been found only in saliva and tears. Two allelic variants (Arg46 and Cys46) are known in the human protein and they are not significantly different in their inhibitory activity against papain and cathepsins B, H, L and S (2). Recombinant Human Cystatin D corresponds to the Arg46 variant. The functions of Cystatin D are largely unknown. However, Cystatin D has been shown to inhibit coronavirus replication at its physiological concentration (0.12‑1.9 μM) and has been suggested to play a protective role against proteases present in the oral cavity (3).


  1. Freije, J.P. et al. (1993) J. Biol. Chem. 268:15737.
  2. Balbin, M. et al. (1994) J. Biol. Chem. 269:23156.
  3. Collins, A.R. and A. Grubb (1998) Oral Microbiol. Immunol. 13:59.

Alternate Names


Entrez Gene IDs

1473 (Human)

Gene Symbol



Additional Cystatin D Products

Product Documents for Recombinant Human Cystatin D Protein, CF

Certificate of Analysis

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Product Specific Notices for Recombinant Human Cystatin D Protein, CF

For research use only

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