Location of the protease-inhibitory region of secretory leukocyte protease inhibitor.

摘要: Secretory leukocyte protease inhibitor (SLPI) is a two-domain protein that inhibits wide range of proteases including chymotrypsin, elastase, and trypsin. Based on its homology to other inhibitors x-ray crystallography an SLPI-chymotrypsin complex it has been proposed the elastase chymotrypsin-inhibitory site in COOH-terminal domain trypsin-inhibitory NH2-terminal domain. We have prepared muteins SLPI by site-directed mutagenesis synthetic gene for protein, followed expression Escherichia coli. The protease-inhibitory activities these indicate leucine 72 at inhibitory chymotrypsin. Unexpectedly, our measurements not Instead they suggest also trypsin, even though amino acid residues sites trypsin are almost always either lysine or arginine.