title: Amino-acid-sequence determination and biological activity of tessulin, a naturally occurring trypsin-chymotrypsin inhibitor isolated from the leech Theromyzon tessulatum.
abstract: We purified a new trypsin-chymotrypsin inhibitor, designated tessulin, from the rhynchobdellid leech Theromyzon tessulatum. This 9-kDa peptide was purified to apparent homogeneity by gel-permeation and anion-exchange chromatographies followed by reverse-phase HPLC. The structure of tessulin was determined by reduction, S-beta-pyridylethylation, trypsin digestion, automated Edman degradation and matrix-assisted laser desorption mass spectrometry (m/z 8985 Da). The 81-amino-acid peptide possesses 16 cysteines and exhibits a 16% sequence similarity with antistasin-type inhibitors. Tessulin inhibits trypsin (Ki 1 pM) and chymotrypsin (Ki 150 pM) and exhibits no activity with thrombin, factor Xa, cathepsin G and elastase. This is the first trypsin-chymotrypsin inhibitor isolated from leeches that does not inhibit elastase or cathepsin G, except for cytin and therin. Furthermore, tessulin, in conjunction with other serine-protease inhibitors isolated from Theromyzon (therin, theromin), significantly diminishes the level of human granulocyte and monocyte activation induced by lipopolysaccharides (10 microg). The combined level of inhibition is higher than that of aprotinin, another serine-protease inhibitor used biomedically. Thus, tessulin may be clinically significant in reducing inflammatory events.
authors.affiliation: Centre de Biologie Cellulaire, Laboratoire d'Endocrinologie des Annélides, Groupe de Neuroimmunité des Hirudinées, UPRES A 8017 CNRS, SN3, Université des Sciences et Technologies de Lille, France.
authors.forename: V
authors.initials: V
authors.lastname: Chopin
authors.forename: G B
authors.initials: GB
authors.lastname: Stefano
authors.forename: M
authors.initials: M
authors.lastname: Salzet
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002918:Chymotrypsin / Q000037:antagonists & inhibitors; D019075:Electrophoresis, Capillary; D007249:Inflammation / Q000188:drug therapy; D007865:Leeches / Q000737:chemistry*; D007962:Leukocytes / Q000187:drug effects; D008070:Lipopolysaccharides / Q000494:pharmacology; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry; D017421:Sequence Analysis; D015842:Serine Proteinase Inhibitors / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014361:Trypsin Inhibitors / Q000737:chemistry
chemical_list: D000276:Adjuvants, Immunologic; D008070:Lipopolysaccharides; D010455:Peptides; D011506:Proteins; D015842:Serine Proteinase Inhibitors; D014361:Trypsin Inhibitors; C116698:tessulin; D002918:Chymotrypsin