CSTA, also known as Stefin A, is thiol protease inhibitors that form complexes with papain and the cathepsins B, H and L. The protein is one of the precursor proteins of the cornified cell envelope in keratinocytes and plays a role in epidermal development and maintenance. CSTA is thought to be a tumor suppressor, since an inverse correlation seems to exist between the level of CSTA and tumor progression, in several malignancies. Source: Recombinant protein corresponding to aa1-98 from human CSTA, fused to His-tag at N-terminal expressed in E. coli. Molecular Weight: ~13.1kD (118aa) Biological Activity: The IC50 value is <1nM. The inhibitory function of Cystatin A on protease activity of papain was measured by a fluorometric assay using Z-FR-AMC at pH 7.5 at 25C. Amino Acid Sequence: MGSSHHHHHH SSGLVPRGSH MIPGGLSEAK PATPEIQEIV DKVKPQLEEK TNETYGKLEA VQYKTQVVAG TNYYIKVRAG DNKYMHLKVF KSLPGQNEDL VLTGYQVDKN KDDELTGF Storage and Stability: May be stored at 4C for short-term only. Aliquot to avoid repeated freezing and thawing.. Store at -20C. Aliquots are stable for 6 months after receipt at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
