Human Secretory Leukocyte Protease Inhibitor SLPI is a protein found in various secretory fluids, including parotid secretions, bronchial, nasal and cervical mucus, and seminal fluid. The protein is a potent inhibitor of a variety of proteolytic enzymes, including the neutrophil proteases, elastase and cathepsin G and the pancreatic proteases chymotrypsin and trypsin. SLPI is an important component of the antiprotease defense of tissues bathed by secretory fluids and could be useful as a therapeutic agent for treatment of the proteolytic damage of tissues seen in degenerative and inflammatory diseases. Recombinant protein corresponding to Ser26-Ala132 from human SLPI, expressed in E. coli. Predicted Molecular Weight: ~12kD Activity: Measured by its ability to inhibit trypsin cleavage of a fluorogenic peptide substrate, McaRPKPVENvalWRK(Dnp)NH2. The IC50 value is 4.0nM, under the described conditions. See Activity Assay Protocol. Storage and Stability: Lyophilized and reconstituted products are stable for 6 months after receipt at -20C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store 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.
