(A) leech-derived human leukocyte elastase inhibitor

Abstract

Inhibitory peptides against protease were studied from a Korean native leech species, Hirudo nipponia. An elastase inhibitor was purified and characterized by using Sephadex G-75 gel filtration, anion exchange chromatography on DEAE-Sepharose and $C_{18}$ reversed phase HPLC column, followed by acetone precipitation and the complete amino acid sequence of the inhibitor was determined. The purified peptide has a molecular weight of 6,119 Da on MALDI mass spectrum. Inhibitory activity of the peptide was examined on the various kind of proteases. Though the inhibitory peptide has a small effect on chymotrypsin and subtilisin, no inhibitory effect on other proteases such as trypsin, pepsin, and papain was observed. The peptide is stable at the wide range of pH 1 to 11 and is heat stable up to $90^\circ C$. The sequence of the peptide was compared with other peptide inhibitors. The amino acid sequence of the peptide shows similarity to subtilisin - chymotrypsin inhibitors from barley and maize and Factor Xa inhibitor, antistasin, from Mexican leech.