Bracht F, Schrör K
Institut für Pharmakologie, Heinrich-Heine-Universität Düsseldorf, Germany.
Biochem Biophys Res Commun. 1994 Apr 29;200(2):933-7. doi: 10.1006/bbrc.1994.1539.
This study was designed to isolate and identify aptamer sequences, acting as thrombin antagonists, from defibrotide, a single-stranded DNA fraction. Two different aptamers were identified: 5'-GGTTGGATTGGTTGG-3' and 5'-GGTTGGATCGGTTGG-3'. A third aptamer: 5'-GGATGGATCGGTTGG-3' was found in the PCR product from the double-stranded defibrotide precursor. All aptamers were potent inhibitors of thrombin-induced platelet aggregation, thromboxane biosynthesis, increase in cytosolic Ca++ and fibrin clot formation, effective concentrations being in the nanomolar range. There was no effect on U 46,619 (thromboxane mimetic) or collagen-induced responses. Similar effects were obtained with unfractionated defibrotide while the "nonsense" oligonucleotide 5'-GGTGGTGGTTGTGGT-3' was inactive. The data suggest that antithrombin effects of defibrotide are caused by aptamers.
本研究旨在从单链DNA组分去纤苷中分离并鉴定作为凝血酶拮抗剂的适配体序列。鉴定出了两种不同的适配体：5'-GGTTGGATTGGTTGG-3'和5'-GGTTGGATCGGTTGG-3'。在双链去纤苷前体的PCR产物中发现了第三种适配体：5'-GGATGGATCGGTTGG-3'。所有适配体都是凝血酶诱导的血小板聚集、血栓素生物合成、胞质Ca++增加和纤维蛋白凝块形成的有效抑制剂，有效浓度在纳摩尔范围内。对U 46,619（血栓素模拟物）或胶原诱导的反应没有影响。未分级的去纤苷也获得了类似的效果，而“无义”寡核苷酸5'-GGTGGTGGTTGTGGT-3'没有活性。数据表明去纤苷的抗凝血酶作用是由适配体引起的。
