Structural features of low-molecular-weight heparins affecting their affinity to antithrombin
Structural features of low-molecular-weight heparins affecting their affinity to antithrombin
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DOI：
10.1160/th09-02-0081
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发表时间：
2009-11-01
影响因子：
6.7
通讯作者：
Torri, Giangiacomo
中科院分区：
文献类型：
--
作者：
Bisio, Antonella;Vecchietti, Davide;Torri, Giangiacomo
作为可能影响其生物活性的不同低分子量肝素（LMWH）结构特征的更广泛研究的一部分，对依诺肝素、亭扎肝素和达肝素进行了分子排阻（SE）色谱法测定的不同链长寡糖分布及其2D-NMR光谱（HSQC）定义的结构表征。三种LMWH还根据其结合抗凝血酶（AT）的能力分成高亲和力（HA）和无亲和力（NA）池。HA级分进一步细分和表征。对于母体LMWH和所选馏分，使用具有三重检测器（TDA）的SE色谱系统测量分子量参数，以获得绝对分子量。SE色谱图清楚表明，依诺肝素始终比亭扎肝素和达肝素更富含短寡糖。除了提供端基和具有不同硫酸酯取代基的单个葡糖胺和糖醛酸残基的含量外，HSQC-NMR光谱还允许我们通过量化二糖序列G-A* 的信号来评估和关联五糖、AT结合序列A-G-A*-I-A（AT-bs）的含量。尽管三种LMWH的HA物质的百分比含量大致相同，但观察到AT-bs的链分布随长度变化的显著差异，AT-bs优先包含在每种LMWH的最长链中。上述信息将有助于确定目前正在进行的结构-活性关系。因此，这项研究是至关重要的，建立LMWH的结构特征和AT介导的抗凝活性之间的相关性。
As part of a more extensive investigation on structural features of different low-molecular-weight heparins (LMWHs) that can affect their biological activities, Enoxaparin,Tinzaparin and Dalteparin were characterised with regards to the distribution of different chain length oligosaccharides as determined by size-exclusion (SE) chromatography, as well as their structure as defined by 2D-NMR spectra (HSQC). The three LMWHs were also fractionated into high affinity (HA) and no affinity (NA) pools with regards to their ability to bind antithrombin (AT). The HA fractions were further subfractionated and characterised. For the parent LMWHs and selected fractions, molecular weight parameters were measured using a SE chromatographic system with a triple detector (TDA) to obtain absolute molecular weights. The SE chromatograms clearly indicate that Enoxaparin is consistently richer in shorter oligosaccharides than Tinzaparin and Dalteparin. Besides providing the content of terminal groups and individual glucosamine and uronic acid residues with different sulfate substituents, the HSQC-NMR spectra permitted us to evaluate and correlate the content of the pentasaccharide,AT-binding sequence A-G-A*-I-A (AT-bs) through quantification of signals of the disaccharide sequence G-A*. Whereas the percent content of HA species is approximately the same for the three LMWHs, substantial differences were observed for the chain distribution of AT-bs as a function of length, with the AT-bs being preferentially contained in the longest chains of each LMWH. The above information will be useful in establishing structure-activity relationships currently under way. This study is therefore critical for establishing correlations between structural features of LMWHs and their AT-mediated anticoagulant activity.