Cystatin B/CSTB Protein, Human (His)

Cystatin B (CSTB) Protein is a member of the cystatin family. Cystatin B/CSTB Protein, Human (His) is the recombinant human-derived Cystatin B/CSTB protein, expressed by E. coli , with N-His labeled tag. The total length of Cystatin B/CSTB Protein, Human (His) is 97 a.a., with molecular weight of ~15 kDa.

Cystatin B/CSTB Protein functions as an intracellular thiol protease inhibitor. Cystatin B/CSTB protein is able to form a dimer stabilized by noncovalent forces, inhibiting papain and cathepsins l, h and b. Cystatin B/CSTB protein is thought to play a role in protecting against the proteases leaking from lysosomes. Evidence indicates that mutations in Cystatin B/CSTB gene are responsible for the primary defects in patients with progressive myoclonic epilepsy (EPM1). The cystatin superfamily encompasses proteins that contain multiple cystatin-like sequences. There are three inhibitory families in the superfamily, including the type 1 cystatins (stefins), type 2 cystatins and kininogens.

Measured by its ability to inhibit papain cleavage of a fluorogenic peptide substrate Z-FR-AMC. The IC₅₀ value is < 30 nM.

Human

E. coli

N-His

Q76LA1 (M2-F98)

1476  [NCBI]

MCGAPSATQPATAETQHIADQVRSQLEEKENKKFPVFKAVSFKSQVVAGTNYFIKVHVGDEDFVHLRVFQSLPHENKPLTLSNYQTNKAKHDELTYF

Approximately 15 kDa

• 
  Greater than 95% as determined by reducing SDS-PAGE.

Lyophilized powder

Lyophilized from a 0.2 μm filtered solution of 50 mM Tris, 50 mM NaCl, pH 8.0 or 50 mM Tris-HCL, 300 mM NaCl, pH 8.0.

<1 EU/μg, determined by LAL method.

It is not recommended to reconstitute to a concentration less than 100 μg/mL in ddH₂O.For long term storage it is recommended to add a carrier protein (0.1% BSA, 5% HSA, 10% FBS or 5% Trehalose).

Stored at -20°C for 2 years. After reconstitution, it is stable at 4°C for 1 week or -20°C for longer (with carrier protein). It is recommended to freeze aliquots at -20°C or -80°C for extended storage.

Room temperature in continental US; may vary elsewhere.