Reexamination of the extent of the activation of Lys78 plasminogen by tissue plasminogen activator in the presence of polymerized fibrin.
The rate of the conversion of Lys78 plasminogen (Lys78-plg) to Lys78 plasmin by tissue plasminogen activator (tPA) was directly quantitated by SDS-PAGE. The apparent second-order rate constant (Kapp) was (0.27 +/- 0.07) x 10(3)/M/s for single-chain tPA and Lys78-plg, and was enhanced approximately 5-fold by fibrinogen and 17-fold by polymerized fibrin. Kapp was (1.57 +/- 0.46) x 10(3)/M/s for two-chain tPA and Lys78-plg, and was enhanced approximately 2.6-fold by fibrinogen and 3.6-fold by fibrin. The factor of the enhancement by polymerized fibrin was far less than in previous reports in which chromogenic substrate was commonly employed.
Urano
T
T
Department of Physiology, Hamamatsu University School of Medicine, Japan.
Takada
Y
Y
Ihara
H
H
Takada
A
A
D001704:Biopolymers; D004357:Drug Synergism; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D005337:Fibrin / Q000737:chemistry / Q000494:pharmacology*; D005341:Fibrinolysin / Q000096:biosynthesis; D006801:Humans; D007700:Kinetics; D010958:Plasminogen / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology; D010959:Tissue Plasminogen Activator / Q000494:pharmacology*
D001704:Biopolymers; D011994:Recombinant Proteins; C103884:lysyl(78) plasminogen; D005337:Fibrin; D010958:Plasminogen; D010959:Tissue Plasminogen Activator; D005341:Fibrinolysin