Department of Anesthesiology, University of Arizona College of Medicine, Tucson, AZ 85719, USA.
MToxins Venom lab LLC, 717 Oregon Street, Oshkosh, WI 54902, USA.
Int J Mol Sci. 2020 Mar 18;21(6):2082. doi: 10.3390/ijms21062082.
Using thrombelastography to gain mechanistic insights, recent investigations have identified enzymes and compounds in and species' neurotoxic venoms that are anticoagulant in nature. The neurotoxic venoms of the four extant species of (the Black and green mambas) were noted to be anticoagulant in nature in human blood, but the mechanisms underlying these observations have never been explored. The venom proteomes of these venoms are unique, primarily composed of three finger toxins (3-FTx), Kunitz-type serine protease inhibitors (Kunitz-type SPI) and <7% metalloproteinases. The anticoagulant potency of the four mamba venoms available were determined in human plasma via thrombelastography; vulnerability to inhibition of anticoagulant activity to ethylenediaminetetraacetic acid (EDTA) was assessed, and inhibition of anticoagulant activity after exposure to a ruthenium (Ru)-based carbon monoxide releasing molecule (CORM-2) was quantified. Black mamba venom was the least potent by more than two orders of magnitude compared to the green mamba venoms tested; further, Black Mamba venom anticoagulant activity was not inhibited by either EDTA or CORM-2. In contrast, the anticoagulant activities of the green mamba venoms were all inhibited by EDTA to a greater or lesser extent, and all had anticoagulation inhibited with CORM-2. Critically, CORM-2-mediated inhibition was independent of carbon monoxide release, but was dependent on a putative Ru-based species formed from CORM-2. In conclusion, there was great species-specific variation in potency and mechanism(s) responsible for the anticoagulant activity of venom, with perhaps all three protein classes-3-FTx, Kunitz-type SPI and metalloproteinases-playing a role in the venoms characterized.
利用血栓弹性描记术获得的机械洞察力，最近的研究已经确定了 和 物种神经毒性毒液中的酶和化合物，它们在本质上是抗凝的。四种现存的 物种（黑曼巴和绿曼巴）的神经毒性毒液在人类血液中被证明具有抗凝作用，但这些观察结果背后的机制从未被探索过。这些毒液的蛋白质组是独特的，主要由三种手指毒素（3-FTx）、Kunitz 型丝氨酸蛋白酶抑制剂（Kunitz 型 SPI）和<7%的金属蛋白酶组成。通过血栓弹性描记术在人血浆中测定了四种曼巴毒液的抗凝效力；评估了对乙二胺四乙酸（EDTA）抑制抗凝活性的敏感性，并量化了暴露于钌（Ru）基一氧化碳释放分子（CORM-2）后对抗凝活性的抑制作用。与测试的绿曼巴毒液相比，黑曼巴毒液的效力低了两个数量级以上；此外，EDTA 或 CORM-2 均不能抑制黑曼巴毒液的抗凝活性。相比之下，绿曼巴毒液的抗凝活性都不同程度地被 EDTA 抑制，所有毒液的抗凝活性都被 CORM-2 抑制。至关重要的是，CORM-2 介导的抑制与一氧化碳释放无关，但与 CORM-2 形成的一种假定的 Ru 基物质有关。总之， 毒液的效力和抗凝活性的机制在物种间存在很大的特异性差异，可能所有三种蛋白质类（3-FTx、Kunitz 型 SPI 和金属蛋白酶）都在特征描述的毒液中发挥作用。
