Merck, C4249-50UG, Cystatin B human

General description
Cystatin B is a member of the type 1 (stefins) superfamily of cystatins. Cystatin B is encoded by the CSTB gene and functions as an intracellular thiol protease inhibitor regulating the activity of members of the papain family and cathepsins B, H, and L. Cystatin B may also protect cellular components from the effects of proteases that leak from lysosomes. Mutations in the CSTB gene are thought to be the primary defect in patients with Progressive Myoclonus Epilepsy (EPM1).
Application
Suitable for use as a cysteine-protease inhibitor. Is tested for suitability as an inhibitor of the enzymatic activity of papain.
Biochem/physiol Actions
Cystatin B was shown to interact with the protein RACK-1, β-spectrin and neurofilament light chain NF-L forming a unique multiprotein complex specifically in the cerebellum, confirming its function in the brain.
Preparation Note
Cystatin B should be reconstituted at 100 μg/mL in steile 25 mM Tris pH 7.5 and 100 mM NaCl. Reconstituted product should be stored in single-use aliquots at -70° C and should be stable for at least 3 months.