CSTB Human, Active
Cystatin-B, Stefin-B, Liver thiol proteinase inhibitor, CPI-B, CSTB, CST6, EPM1, PME, STFB
Greater than 95.0% as determined by SDS-PAGE.
Description
CSTB Human Recombinant produced in E.Coli is a single, non-glycosylated polypeptide chain containing 118 amino acids (1-98 a.a.) and having a molecular mass of 13kDa.
CSTB is fused to a 20 amino acid His tag at N-Terminus and purified by proprietary chromatographic techniques.
Product Specs
Cystatin B (CSTB) is a protein, specifically an anti-protease, that is believed to play a role in myoclonus epilepsy. It belongs to the encompasses proteins family and possesses multiple cystatin-like sequences. The cystatin superfamily consists of cysteine protease inhibitors, although some members, including CSTB, lack this inhibitory function. CSTB can form stable dimers through noncovalent bonds, and it plays a crucial role in protecting cells from damage caused by leaking lysosomal proteases. Within cells, Cystatin B is found in the lysosomes, nucleus, and cytoplasm.
Recombinant Human CSTB, produced in E. coli, is a single, non-glycosylated polypeptide chain consisting of 118 amino acids (specifically, amino acids 1 to 98). It has a molecular weight of 13 kDa. The CSTB protein is fused to a 20 amino acid His tag at its N-terminus and is purified using proprietary chromatographic methods.
The CSTB solution has a concentration of 1 mg/ml and is formulated in a buffer containing 50mM NaCl and 20mM Tris-HCl at a pH of 8.0.
For short-term storage (up to 2-4 weeks), the CSTB solution should be kept refrigerated at 4°C. For longer storage, it is recommended to freeze the solution at -20°C. To ensure stability during long-term storage, adding a carrier protein like HSA or BSA to a final concentration of 0.1% is advisable. It's important to avoid repeatedly freezing and thawing the solution.
The purity of the CSTB protein is greater than 95%, as determined by SDS-PAGE analysis.
The IC50 value, which represents the concentration of CSTB required to inhibit 50% of the protease activity of papain, is less than 3.0 nM. This inhibitory activity was measured using a fluorometric assay with Z-FR-AMC as the substrate at a pH of 7.5 and a temperature of 25°C.
Cystatin-B, Stefin-B, Liver thiol proteinase inhibitor, CPI-B, CSTB, CST6, EPM1, PME, STFB
MGSSHHHHHH SSGLVPRGSH MMCGAPSATQ PATAETQHIA DQVRSQLEEK ENKKFPVFKA VSFKSQVVAG TNYFIKVHVG DEDFVHLRVF QSLPHENKPL TLSNYQTNKA KHDELTYF
Product Science Overview
Cystatin-B, also known as stefin B or liver thiol proteinase inhibitor, is a protein encoded by the CSTB gene in humans . It belongs to the cystatin superfamily, which includes proteins containing multiple cystatin-like sequences. Some members of this family are active cysteine protease inhibitors, while others may have lost or never acquired this inhibitory activity .
Cystatin-B is an intracellular inhibitor that regulates the activities of cysteine proteases of the papain family, such as cathepsins B, H, and L . It is a tightly binding reversible inhibitor, meaning it can bind to and inhibit these proteases but can also release them under certain conditions . This regulation is crucial for maintaining cellular homeostasis and preventing uncontrolled protease activity, which can lead to cellular damage.
Recombinant human Cystatin-B is a bioactive protein produced using recombinant DNA technology. It is typically expressed in Escherichia coli and purified to high levels of purity (>95%) with low endotoxin levels (<1 EU/µg) . The recombinant form retains its biological activity and is used in various research applications, including functional assays, SDS-PAGE, and mass spectrometry .
Recombinant human Cystatin-B is used in research to study its inhibitory effects on cysteine proteases and its role in various biological processes. It is also used in assays to measure the activity of proteases and to screen for potential inhibitors of these enzymes . Additionally, it serves as a valuable tool in understanding the molecular mechanisms underlying diseases associated with protease dysregulation.
