Hi. Jung et al., ISOLATION AND CHARACTERIZATION OF GUAMERIN, A NEW HUMAN-LEUKOCYTE ELASTASE INHIBITOR FROM HIRUDO-NIPPONIA, The Journal of biological chemistry, 270(23), 1995, pp. 13879-13884
A new human leukocyte elastase inhibitor was extracted and purified fr
om a Korean native leech Hirudo nipponia. The inhibitor, called guamer
in, has a molecular weight of 6,110 and shows inhibition constant (K-i
) of 8.1 x 10(-14) M. It is stable at a wide range of pH from 1 to 11
and heat-stable up to 90 degrees C. The complete amino acid sequence o
f guamerin reveals a cysteine-rich polypeptide of 57 amino acid residu
es that shows no similarity to any known elastase inhibitors but has 5
1% sequence homology with hirustasin, Guamerin has identical spacing o
f 10 cysteine residues as antistasin-type serine proteinase inhibitors
, but the P1 reactive site residue is Met(36) instead of Arg, The neig
hboring sequence of the reactive site consists primarily of hydrophobi
c amino acid residues, Based on examinations of the target proteinases
and the reactive site specificity, guamerin is a new low molecular we
ight protein that inhibits elastases.