Open AccessAmino acid sequence determination and biological activity of therin, a naturally occuring specific trypsin inhibitor from the leech Theromyzon tessulatum
Author(s) -
Chopin Vincent,
Matias Isabel,
Stefano George B.,
Salzet Michel
Publication year - 1998
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.1998.2540565.x
Subject(s) - leech , edman degradation , trypsin , peptide sequence , chemistry , aprotinin , trypsin inhibitor , biochemistry , peptide , chromatography , microbiology and biotechnology , biology , enzyme , medicine , surgery , world wide web , computer science , gene
We purified a trypsin inhibitor, designated therin, from the rhynchobdellid leech Theromyzon tessulatum . Therin was purified to apparent homogeneity by gel‐permeation and anion‐exchange chromatography followed by reverse‐phase HPLC. By a combination of reduction and S ‐β‐pyridylethylation, Edman degradation and electrospray mass spectrometry measurement, the complete sequence of therin (48 amino acid residues; m / z , 5376.35 ± 0.22 Da) was determined. Therin exhibits an approximately 30 % sequence similarity with peptides of the antistasin‐type inhibitors family, i.e. the first and second domains of antistasin, hirustasin, ghilanthen and guamerins (I, II). Therin is a tight‐binding inhibitor of trypsin ( K i , 45 ± 12 pM) and has no action towards elastase or cathepsin G. Furthermore, therin (10 −6 M) in conjunction with theromin, a Theromyzon thrombin inhibitor (10 −6 M) significantly diminish the level of human leucocytes activation induced by lipopolysaccharide (10 μg) in a manner similar to that of aprotinin. These data suggest a leech trypsin inhibitor with possible biomedical signifance.