[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.

[Isolation and characteristics of antistreptokinase antibodies from blood serum of myocardial infarct patients treated with streptokinase]. / Vydilennia ta kharakterystyka antystreptokinaznykh antytil iz syrovatky krovi khvorykh na infarkt miokarda, iakykh likuvaly streptokinazoiu.

Antistreptokinase IgG (antiSK IgG) from blood of 8 patients with acute myocardial infarction that were treated by streptokinase (SK) has been investigated. AntiSK IgG contained 1.8% of total serum IgG. They had high affinity to SK (K50% approximately 10 nM) and inhibited activation of plasminogen (Pg) by SK with K50% approximately 6 nM. AntiSK IgG were bound with chymothriptic fragments of SK with affinity decreased in the set of fragments: 47 > 36 > 30 > 17 > or = 11 > 7 kDa. 11 linear epitopes of antiSK IgG were localized in I1-S12, T43-M70, G139-Q152, T163-I190, T193-S222, F241-Y252, Y275-P286, T315-L336, I365-E376, S379-T390 and Y397-N410 sites of SK primary structure using SK decapeptides. 70% of antibodies were bound with T43-M70 (38.3%), T315-L336 (13.2%) and Y397-N410 (17.7%) SK sequences located in alpha and gamma SK domains. By depletion of antiSK IgG on Pg-SK complex it was shown that 80-85% of antiSK IgG bound to Pg-SK complex, 47.9% of that contained antibodies with epitopes located in I1-S12, T43-M70, T193-S222 and S379-T390 SK sequences, and rest of IgG had probably spatial epitopes. Unbound with Pg-SK complex antibodies inhibited activation of Pg by SK with higher affinity (Ki approximately 1.2 nM) in comparison with total antiSK IgG fraction. The role of different sites in antigenity of SK and in Pg-SK complex formation is discussed.

[Val709-Glu724 streptokinase binding site on plasminogen interacts with streptokinase sequence Thr361-Arg372 during plasminogen-streptokinase complex formation]. / Sait zv'iazuvannia streptokinazy na plazminoheni Val709-Glu724 vzaiemodiie z diliankoiu Thr361-Arg372 streptokinazy pid chas utvorennia plazminohen-streptokinaznoho kompleksu.

Localization of the human plasminogen binding site on the streptokinase of complementary Val709-Glu724 plasminogen being crucial one in providing for the plasminogen streptokinase complex activity has been investigated. Experiments were performed with streptokinase fragments and synthetic decapeptides, antiplasminogen monoclonal anti-body IV-1c and synthetic peptide corresponding to Val709-Gly718 sequence of human plasminogen. It was found that plasminogen sequence Val709-Glu724 interacted with Thr361-Arg372 sequence of strepto-kinase.