聚戊糖硫酸酯对抗凝血酶III灭活凝血酶和Xa因子的影响。

Effect of a pentosan polysulphate upon thrombin and factor Xa inactivation by antithrombin III.

作者信息

Scully M F, Kakkar V V

出版信息

Biochem J. 1984 Sep 15;222(3):571-8. doi: 10.1042/bj2220571.

DOI:10.1042/bj2220571

PMID:6207810

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1144217/

Abstract

The kinetics of inhibition of human and bovine alpha-thrombin and human factor Xa by antithrombin III were examined under pseudo-first-order conditions as a function of the concentration of pentosan polysulphate [a fully sulphated (beta 1-4)-linked D-xylopyranose with a single laterally positioned 4-O-methyl-alpha-D-glucuronic acid]. Double-reciprocal plots of the observed first-order rate constant against concentration of pentosan polysulphate gave straight lines, intercepts on the axes giving values for maximum increase in second-order rate constant (by calculation) and apparent dissociation constant. These values were: for human alpha-thrombin 1.52 X 10(7) M-1 . min-1 and 3.6 microM respectively, for bovine alpha-thrombin 6.56 X 10(6) M-1 . min-1 and 0.16 microM and for factor Xa 6.86 X 106 M-1 . min-1 and 20 microM. In the presence of pentosan polysulphate the dissociation constant for the initial complex of antithrombin III and thrombin was shown to be reduced from approx. 2 X 10(-3) M to 61 X 10(-6) M without apparent change in the limiting rate constant of 750 min-1. An oligosaccharide (primarily 8-10 saccharide units) prepared from heparin and with high affinity for antithrombin III but low potency in the thrombin-antithrombin III interaction did not diminish the rate of interaction catalysed by pentosan polysulphate. The catalysis was shown to be due to a weak electrostatic interaction, since it was completely reversed by concentrations of NaCl greater than 0.3 M. It is concluded that the mechanism is independent of the heparin high-affinity binding site on antithrombin III and is probably due to binding of the high-charge-density polysaccharide to the proteinase. It is calculated that the acceleration in rate achieved, although lower than that of heparin, approaches that required to be of physiological significance and may be of importance in the anticoagulation role of antithrombin III at sites of high charge density which may occur in vivo.

摘要

在准一级条件下，研究了抗凝血酶III对人及牛α-凝血酶和人因子Xa的抑制动力学，该动力学是戊聚糖多硫酸盐（一种完全硫酸化的、以（β1-4）连接的D-木吡喃糖，带有一个横向定位的4-O-甲基-α-D-葡糖醛酸）浓度的函数。观察到的一级速率常数对戊聚糖多硫酸盐浓度的双倒数图给出直线，轴上截距给出二阶速率常数最大增加量（通过计算）和表观解离常数的值。这些值分别为：人α-凝血酶1.52×10⁷ M⁻¹·min⁻¹和3.6 μM，牛α-凝血酶6.56×10⁶ M⁻¹·min⁻¹和0.16 μM，因子Xa 6.86×10⁶ M⁻¹·min⁻¹和20 μM。在戊聚糖多硫酸盐存在下，抗凝血酶III与凝血酶初始复合物的解离常数显示从约2×10⁻³ M降至61×10⁻⁶ M，而极限速率常数750 min⁻¹无明显变化。一种由肝素制备的寡糖（主要为8 - 10个糖单元），对抗凝血酶III具有高亲和力，但在凝血酶 - 抗凝血酶III相互作用中效力低，并未降低戊聚糖多硫酸盐催化的相互作用速率。催化作用显示是由于弱静电相互作用，因为大于0.3 M的NaCl浓度可使其完全逆转。得出的结论是，该机制独立于抗凝血酶III上的肝素高亲和力结合位点，可能是由于高电荷密度多糖与蛋白酶的结合。经计算，实现的速率加速尽管低于肝素，但接近具有生理意义所需的速率，并且可能在体内可能出现的高电荷密度部位抗凝血酶III的抗凝作用中具有重要意义。