Isolation and characterization of four serine proteinase inhibitors (serpins) from hemolymph of Manduca sexta

Abstract

Four serine proteinase inhibitors have been isolated from hemolymph of fifth instar larvae of Manduca sexta. One of these, an inhibitor specific for elastase, has been previously shown to be a member of the serpin family of serine proteinase inhibitors. Of the three remaining inhibitors, two are specific for chymotrypsin and one for trypsin. The four inhibitors have molecular weights of approx. 47,000 and isoelectric points between 4.4 and 4.8. The four proteins have very similar amino acid compositions, and NH 2-terminal sequence analysis suggests that they represent members of a gene family.