Cystatin-B, Stefin-B, Liver thiol proteinase inhibitor, CPI-B, CSTB, CST6, EPM1, PME, STFB
Cystatin B or CSTB, is an protein (anti-protease) that is suspected to be involved in myoclonus epilepsy. As part of the encompasses proteins family, it has many cystatin-like sequences. Part of the cystatin superfamily are cysteine protease inhibitors; part don’t have the ability. CSTB can create a dimer that is stable because of noncovalent bonds and has a crucial part in shielding from lysosomal proteases leaking. Cystatin B can be found in the lysosomes, nucleus & the cytoplasm in cells.
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.
The CSTB solution (1mg/1ml) contains 50mM NaCl and 20mM Tris-HCl buffer (pH 8.0).
For long term storage it is recommended to add a carrier protein (0.1% HSA or BSA).
Avoid multiple freeze-thaw cycles.
Greater than 95.0% as determined by SDS-PAGE.
The IC50 value is < 3.0nM. The inhibitory function of Cystatin B on protease activity of papain was measured by a fluorometric assay using Z-FR-AMC at pH 7.5 at 25˚C.
Amino acid sequence
MGSSHHHHHH SSGLVPRGSH MMCGAPSATQ PATAETQHIA DQVRSQLEEK ENKKFPVFKA VSFKSQVVAG TNYFIKVHVG DEDFVHLRVF QSLPHENKPL TLSNYQTNKA KHDELTYF