
- SynonymCST4,Cystatin-4,Cystatin-S,Cystatin-S5,Cystatin-SA-III
- SourceHuman Cystatin S, His Tag (CS4-H5223) is expressed from human 293 cells (HEK293). It contains AA Ser 21 -Ala 141(Accession # AAH65714).Predicted N-terminus: Ser 21Request for sequence
- Molecular Characterization
This protein carries a polyhistidine tag at the C-terminus.
The protein has a calculated MW of 15.0 kDa. The protein migrates as 15 kDa under reducing (R) condition (SDS-PAGE).
- EndotoxinLess than 1.0 EU per μg by the LAL method.
- Purity
>95% as determined by SDS-PAGE.
- Formulation
Lyophilized from 0.22 μm filtered solution in 25 mM MES, 150 mM NaCl, pH6.0. Normally trehalose is added as protectant before lyophilization.
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- Reconstitution
Please see Certificate of Analysis for specific instructions.
For best performance, we strongly recommend you to follow the reconstitution protocol provided in the CoA.
- Storage
For long term storage, the product should be stored at lyophilized state at -20°C or lower.
Please avoid repeated freeze-thaw cycles.
This product is stable after storage at:
- -20°C to -70°C for 12 months in lyophilized state;
- -70°C for 3 months under sterile conditions after reconstitution.

Human Cystatin S, His Tag on SDS-PAGE under reducing (R) condition. The gel was stained overnight with Coomassie Blue. The purity of the protein is greater than 95%.
- BackgroundCystatin-4 (CST4) is also known as Cystatin-S, Salivary acidic protein 1, which is a secreted protein, which belongs to the cystatin family. Cystatin-S is expressed in submandibular and sublingual saliva but not in parotid saliva (at protein level) and is also expressed in saliva, tears, urine and seminal fluid. Cystatin-4 / Cystatin S strongly inhibits papain and ficin, partially inhibits stem bromelain and bovine cathepsin C, but does not inhibit porcine cathepsin B or clostripain. Papain is inhibited non-competitively.
- References
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