Reaction of human α2‐antiplasmin and plasmin Stopped‐flow fluorescence kinetics

FEBS Letters

Bangert, Kristian¹  Thorsen, Sixtus¹  Christensen, Ulla² 

[1] Department of Clinical Biochemistry KB 3-01-1, Rigshospitalet, DK-2100 Copenhagen, Denmark;Chemical Laboratory IV, University of Copenhagen, DK-2100 Copenhagen, Denmark

关键词: Plasmin;    α 2-Antiplasmin;    Stopped-flow fluorescence;    Kinetics;    Lysine-binding site;    t-AMCHA;    trans-4-(aminomethyl)cyclohexane-1-car-boxylic acid;    α 2AP;    α 2-antiplasmin;    LBS;    lysine-binding site;    VLKpNA;    H-d-Val-Leu-Lys-p-nitroanilide;    efkpNA;    pyro-Glu-Phe-Lys-p-nitroanilide;   

DOI  :  10.1016/0014-5793(96)00429-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The interaction of human plasmin with human α₂-antiplasmin was measured in the presence and absence of lysine-binding ligands using the corresponding active site fluorescence changes. The stopped-flow method allows for direct determination of reliable values of the second order rate constant for the fast association step of plasmin and α ₂-antiplasmin in the absence of another interacting compound, e.g. a plasmin substrate. At pH 7.4,25°C, k ₁= 2.2 X 10⁷ M ⁻¹ s ⁻¹ was obtained. Substantial reductions in k ₁ were seen in the presence of trans-4-(aminomethyl)cyclohexane-1-carboxylic acid at concentrations corresponding to lysine-binding site interactions at kringle 4 of plasmin; at saturation the rate constant is reduced 20-fold, whereas the effect of saturation of kringle 1 is only a 2-fold reduction. It is thus found that the interaction of α ₂-antiplasmin with the lysine-binding site of kringle 1 is of little importance compared with that of kringle 4 in regulating the inhibition reaction of plasmin with α ₂-antiplasmin. Similar results were recently obtained for the bovine plasmin-bovine α ₂-antiplasmin reaction (Christensen et al. (1995) Biochem. J. 305, 97–102).

【 授权许可】

Unknown