Premium
Characterization of Crosslinking Sites in Fibrinogen for Plasminogen Activator Inhibitor 2 (PAI‐2)
Author(s) -
RITCHIE HELEN,
LAWRIE LAURA C.,
MOSESSON MICHAEL W.,
BOOTH NUALA A.
Publication year - 2001
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.2001.tb03508.x
Subject(s) - factor xiiia , chemistry , fibrin , fibrinolysis , fibrinogen , lysine , biochemistry , plasminogen activator , tissue transglutaminase , lysis , microbiology and biotechnology , enzyme , amino acid , immunology , biology , medicine , endocrinology , psychiatry
A bstract : PAI‐2 is a serpin that can be crosslinked to fibrin(ogen) via the Gln‐Gln‐Ile‐Gln sequence (residues 83–86). We have characterized the lysine residues in fibrinogen to which PAI‐2 is crosslinked by tissue transglutaminase and factor XIIIa. There was no competition with the crosslinking of α 2 ‐antiplasmin, another inhibitor of fibrinolysis, which was specific for Lys 303 in the Aα chain. PAI‐2 was crosslinked to several lysine residues, all in the Aα chain, 148, 176, 183, 230, 413, and 457, but not to Lys 303. The contrast with α 2 ‐antiplasmin was clear from studies with truncated fibrinogens and competition by peptides. This was confirmed and extended by mass spectrometry of peptides after protease digestion of crosslinked products, which identified the lysine residues to which the inhibitors were crosslinked. PAI‐2 remained active after cross‐linking and inhibited fibrin breakdown, even by two‐chain t‐PA. Thus, a second inhibitor of fibrinolysis, in addition to α 2 ‐antiplasmin, is crosslinked to fibrin and protects it from lysis.