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Inhibition of coagulation factors by recombinant barley serpin BSZx
Author(s) -
Dahl Søren W.,
Rasmussen Søren K.,
Petersen Lars C.,
Hejgaard Jørn
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00940-4
Subject(s) - serpin , plasmin , kallikrein , trypsin , chemistry , biochemistry , thrombin , microbiology and biotechnology , chymotrypsin , serine proteinase inhibitors , chymotrypsinogen , antithrombin , plasminogen activator , zymogen , proteolysis , serine protease , protease , enzyme , biology , heparin , platelet , immunology , gene , endocrinology
Barley serpin BSZx is a potent inhibitor of trypsin and chymotrypsin at overlapping reactive sites (Dahl, S.W., Rasmussen, S.K. and Hejgaard, J. (1996) J. Biol. Chem., in press). We have now investigated the interactions of BSZx with a range of serine proteinases from human plasma, pancreas and leukocytes, a fungal trypsin and three subtilisins. Thrombin, plasma kallikrein, factor VIIa/tissue factor and factor Xa were inhibited by BSZx at heparin independent association rates ( k ass ) of 4.5 × 10 3 −1.3 × 10 5 M −1 s −1 at 22°C. Only factor Xa tunred a significant fraction of BSZx over as substrate. Complexes of these proteinase with BSZx resisted boiling in SDS, and amino acid sequencing showed that cleavage in the reactive center loop only occurred after P 1 Arg. Activated protein C and leukocyte elastase were slowly inhibited by BSZx ( k ass = 1−2 × 10 2 M −1 s −1 ) whereas factor XIIa, urokinase and tissue type plasminogen activator, plasmin and pancreas kallikrein and elastase were not or only weakly affected. The inhibition pattern with mammalian proteinases reveal a specificity of BSZx similar to that of antithrombin III. Trypsin from Fusarium was not inhibited while interaction with subtilisin Carlsberg and Novo was rapid but most BSZx was cleaved as a substrate. Identification of a monoclonal antibody specific for native BSZx indicate that complex formation and loop cleavage result in similar conformational changes.