A CYSTEINE-RICH SERINE-PROTEASE INHIBITOR (GUAMERIN-II) FROM THE NON-BLOOD SUCKING LEECH WHITMANIA-EDENTULA - BIOCHEMICAL-CHARACTERIZATION AND AMINO-ACID-SEQUENCE ANALYSIS
Dr. Kim et al., A CYSTEINE-RICH SERINE-PROTEASE INHIBITOR (GUAMERIN-II) FROM THE NON-BLOOD SUCKING LEECH WHITMANIA-EDENTULA - BIOCHEMICAL-CHARACTERIZATION AND AMINO-ACID-SEQUENCE ANALYSIS, Journal of enzyme inhibition, 10(2), 1996, pp. 81-91
A cysteine-rich serine protease inhibitor (Guamerin II) was isolated f
rom the non-blood sucking leech Whitmania edentula. The new inhibitor
was identified as a low molecular weight (6,012 Da) polypeptide with s
ome sequence similarities to antistasin, hirustasin and guamerin. The
inhibitor contained 56 amino acid residues with 76.8% sequence similar
ity to guamerin, 48.2% to hirustasin and 28.6% to the first domain of
antistasin. This new inhibitor was the first completely sequenced seri
ne protease inhibitor from a non-blood sucking leech. Analysis of the
inhibitor revealed that it was active against neutrophil elastase and
chymotrypsin, but had no activity against a variety of other proteases
. The P1 reactive site residue was identified as methionine and the re
sidues surrounding the P1 sire were hydrophobic amino acids. The prima
ry structure of the inhibitor showed no similarity to well-known elast
ase inhibitors from leeches such as eglin.