1. Recombinant Proteins
  2. Enzymes & Regulators
  3. Protease Inhibitors Cystatin Family
  4. Cystatin B
  5. Cystatin B/CSTB Protein, Human (His)

Cystatin B/CSTB Protein, Human (His)

Cat. No.: HY-P72965
COA Handling Instructions

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.

For research use only. We do not sell to patients.

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  • Biological Activity

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Description

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.

Background

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.

Biological Activity

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

Species

Human

Source

E. coli

Tag

N-His

Accession

Q76LA1 (M2-F98)

Gene ID
Molecular Construction
N-term
His
CSTB (M2-F98)
Accession # Q76LA1
C-term
Synonyms
Cystatin B; CSTB; Stefin B; EPM1
AA Sequence

MCGAPSATQPATAETQHIADQVRSQLEEKENKKFPVFKAVSFKSQVVAGTNYFIKVHVGDEDFVHLRVFQSLPHENKPLTLSNYQTNKAKHDELTYF

Molecular Weight

Approximately 15 kDa

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

Lyophilized powder

Formulation

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.

Endotoxin Level

<1 EU/μg, determined by LAL method.

Reconstitution

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).

Storage & Stability

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.

Shipping

Room temperature in continental US; may vary elsewhere.

Documentation
Help & FAQs
  • Do most proteins show cross-species activity?

    Species cross-reactivity must be investigated individually for each product. Many human cytokines will produce a nice response in mouse cell lines, and many mouse proteins will show activity on human cells. Other proteins may have a lower specific activity when used in the opposite species.

  • Reconstitution Calculator

  • Dilution Calculator

  • Specific Activity Calculator

The reconstitution calculator equation

Volume (to add to vial) = Mass (in vial) ÷ Desired Reconstitution Concentration

Volume (to add to vial) = Mass (in vial) ÷ Desired Reconstitution Concentration
= ÷

The dilution calculator equation

Concentration (start) × Volume (start) = Concentration (final) × Volume (final)

This equation is commonly abbreviated as: C1V1 = C2V2

Concentration (start) × Volume (start) = Concentration (final) × Volume (final)
× = ×
C1   V1   C2   V2

The specific activity calculator equation

Specific Activity (Unit/mg) = 106 ÷ Biological Activity (ED50)

Specific Activity (Unit/mg) = 106 ÷ Biological Activity (ED50)
Unit/mg = 106 ÷ ng/mL

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Product Name:
Cystatin B/CSTB Protein, Human (His)
Cat. No.:
HY-P72965
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