Low-molecular-weight compounds with anticoagulant activity from the scorpion Heterometrus laoticus venom

Abstract

Low-molecular-weight compounds with anticoagulant activity were isolated from the scorpion Heterometrus laoticus venom. The determination of the structure of the isolated compounds by nuclear magnetic resonance and mass spectrometry showed that one of the isolated compounds is adenosine, and the other two are dipeptides leucyl-tryptophan and isoleucyl-tryptophan. The anticoagulant properties of adenosine, which is an inhibitor of platelet aggregation, is well known, but its presence in scorpion venom is shown for the first time. The ability of leucyl-tryptophan and isoleucyl-tryptophan to slow down blood clotting and their presence in scorpion venom are also established for the first time.

Anticoagulant Activity of Low-Molecular Weight Compounds from Heterometrus laoticus Scorpion Venom

“…The most abundant fraction, 5.21 (Figure 1), was also purified under conditions used for purification of fraction 5.22 and the structure of purified compound was analyzed as well. Analysis of purified substances indicated that fraction 5.5 corresponds to adenosine, fraction 5.21—to dipeptide LeuTrp and fraction 5.22—to dipeptide IleTrp [17]. The large quantities of dipeptides were prepared by peptide synthesis and their anticoagulant activity was analyzed in detail.…”

“…The anticoagulant activity of both dipeptides on the whole mice blood was determined by the Burker’s method [19], and when tested on the whole blood, the synthetic dipeptides showed significant increases in clotting time [17]. To study anticoagulant activity, the synthetic dipeptides were injected into the lateral vein of the mouse tail at a dose of 7.8 nmoles/g, which corresponds to maximal calculated concentration of 110 µM in the peripheral blood.…”

“…Previously, we have shown that the fractions obtained by gel filtration of Heterometrus laoticus scorpion venom affect the processes of blood coagulation [16] and the structures of low-molecular anticoagulants were established [17]. In the present work, we determined their anticoagulant activity.…”

“…Determination of their structure showed that one compound was well known anticoagulant adenosine, while the other two were dipeptides LeuTrp and IleTrp [17]. The anticoagulant activity of the isolated substances was studied using standard tests for plasma coagulation (APTT, PTT and TT), whole blood clotting test in vitro and bleeding assay in vivo.…”

“…The structures of the compounds isolated from fractions 5.5, 5.21 and 5.22 were determined as described [17]. In brief, the molecular mass of the compound from fraction 5.5 was 267.8 Da close to the mass of adenosine (267.2 Da).…”