Elastase inhibitor from mammalian neutrophil cytosol.

Bovine, pig and horse leukocyte elastase inhibitors represent the first example of functionally active intracellular serpin. Sequence analysis yields data indicating that the reactive site encompasses P1-P'1 Ala-Met sequence. Oxidation of swine (as well as equine) inhibitor reduced its association rate constants kon with the tested enzymes (by at least 1 order of magnitude). However in case of bovine inhibitor, only a slight reduction has been observed for human neutrophil elastase but not for chymotrypsin or pancreatic elastase.