[Plasminogen activation by antiplasminogen monoclonal antibody IV-1C. Properties and mechanism of reaction]. / Aktyvatsiia plazminhenu antyplazminohenovym monoklonal;nym antytilom IV-1c. Vlastyvosti ta mekhanizm reaktsiï

In review the results of investigation of plasminogen(Pg) activation by antiplasminogen monoclonal antibody IV-1c have been presented. Antigenic determinant of IV-1c was localized in Val709-Gly718 site of Pg protease domain. IV-1c completely inhibited the Pg activation by streptokinase, but increased the rate of Pg activation by t-PA and urokinase. Catalytic properties of plasmin in complex with IV-1c were studied. It was found that IV-1c induced catalytic activity in Pg-IV-1c complex. It was shown that Pg and IV-1c interacts in complex by two-centre mechanism: IV-1c binds with Pg by paratope and by N-terminal lysine of gamma-chain and Pg binds to IV-1c by one of the lysine binding sites and by V709-G718 site of protease domain. The influence of pH, temperature, 1.5 mM Ca2+, Mg2+, Sr2+, Ba2+, Co2+, Ni2+ cations and 10 mM Cl-, F-, Ac-, SO4(2-), HPO4(2-) anions on lag and fast phases of Pg activation by VI-1c was investigated. It was revealed that Val709-Gly718 site was determining in Pg activation by IV-1c and streptokinase.

[Plasminogen binding with decapeptide and polypeptide fragments of streptokinase]. / Zv'iazuvannia plazminohena z dekapeptydnymy ta polipeptydnymy frahmentamy sterptokinazy.

The plasminogen binding with streptokinase decapeptides, modeling the primary structure of molecule, and chymotryptic fragments of streptokinase have been investigated. The immunoenzymatic assay has shown that plasminogen binds to all streptokinase fragments with the decreasing affinity in the set of fragments: 36 > 30 > 17 > 7 > 11 kDa. Location of the binding sites in streptokinase primary structure was performed using the immobilized decapeptides on plastic pins adopted to IEA. In the presence of 10 mM 6-aminohexanoic acid 11 sites for human Glu- and mini-plasminogens, pig and bovine plasminogens binding have been found. They were of the same location for human, bovine and pig plasminogens. 3 sites were located in plasminogen alpha-domain--T43-A72, N113-T126, Q133-V158, 5 sites in beta-domain--T163-L188, A203-S222, Q239-I264, Y275-L294, T315-L340, and 3 sites in gamma-domain--T361-R362, N377-E392, T397-N410. Participation of linear part of streptokinase polypeptide chain in plasminogen--streptokinase complex formation is suggested.