Binding of tissue-type plasminogen activator to lysine, lysine analogues, and fibrin fragments.
Human tissue-type plasminogen activator (t-PA) consists of five domains designated (starting from the N-terminus) finger, growth factor, kringle 1, kringle 2, and protease. The binding of t-PA to lysine-Sepharose and aminohexyl-Sepharose was found to require kringle 2. The affinity for binding the lysine derivatives 6-aminohexanoic acid and N-acetyllysine methyl ester was about equal, suggesting that t-PA does not prefer C-terminal lysine residues for binding. Intact t-PA and a variant consisting only of kringle 2 and protease domains were found to bind to fibrin fragment FCB-2, the very fragment that also binds plasminogen and acts as a stimulator of t-PA-catalyzed plasminogen activation. In both cases, binding could completely be inhibited by 6-aminohexanoic acid, pointing to the involvement of a lysine binding site in this interaction. Furthermore, the second site in t-PA involved in interaction with fibrin, presumably the finger, appears to interact with a part of fibrin, different from FCB-2.
de Munk
G A
GA
Gaubius Institute TNO and Medical Biological Laboratory, Leiden, The Netherlands.
Caspers
M P
MP
Chang
G T
GT
Pouwels
P H
PH
Enger-Valk
B E
BE
Verheijen
J H
JH
D000818:Animals; D001665:Binding Sites; D002846:Chromatography, Affinity; D006224:Cricetinae; D004591:Electrophoresis, Polyacrylamide Gel; D005337:Fibrin / Q000378:metabolism*; D006801:Humans; D008024:Ligands; D008239:Lysine / Q000031:analogs & derivatives / Q000378:metabolism*; D010959:Tissue Plasminogen Activator / Q000302:isolation & purification / Q000378:metabolism*
D008024:Ligands; D005337:Fibrin; D010959:Tissue Plasminogen Activator; D008239:Lysine