Inhibition by tranexamic acid of the conversion of single-chain tissue plasminogen activator to its two chain form by plasmin: the presence on tissue plasminogen activator of a site to bind with lysine binding sites of plasmin.
The addition of tranexamic acid inhibited the conversion of single chain tissue plasminogen activator (sct-PA) to its two chain form (tct-PA) by plasmin. Increase in the concentrations of tranexamic acid resulted in more inhibition of the conversion, with 50% inhibition being obtained at 0.251 mM of the concentration of tranexamic acid. The addition of the fragments of plasminogen such as kringle 1 to 3 (K1-3), and K4 resulted in the facilitation of the conversion of sct-PA to tct-PA by plasmin. The addition of tranexamic acid to the mixture of sct-PA and K4 inhibited the rate of the conversion of sct-PA by plasmin. These results suggest that binding of lysine binding sites of plasmin or plasminogen with sct-PA enhanced its conversion to tct-PA by plasmin, and that there is a site on a t-PA molecule to bind to plasminogen or plasmin.
Takada
A
A
Department of Physiology, Hamamatsu University, School of Medicine, Shizuoka, Japan.
Takada
Y
Y
D000818:Animals; D001665:Binding Sites; D003509:Cyclohexanecarboxylic Acids / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D005341:Fibrinolysin / Q000378:metabolism*; D006801:Humans; D008239:Lysine / Q000378:metabolism*; D051379:Mice; D010446:Peptide Fragments / Q000378:metabolism; D011485:Protein Binding; D010959:Tissue Plasminogen Activator / Q000378:metabolism*; D014148:Tranexamic Acid / Q000494:pharmacology*
D003509:Cyclohexanecarboxylic Acids; D010446:Peptide Fragments; D014148:Tranexamic Acid; D010959:Tissue Plasminogen Activator; D005341:Fibrinolysin; D008239:Lysine