Department of Studies in Biochemistry, University of Mysore, Manasagangotri, Mysore, 570 006, India.
J Thromb Thrombolysis. 2010 Apr;29(3):340-8. doi: 10.1007/s11239-009-0379-2.
A high molecular mass, non toxic metalloprotease the NN-PF3 with the bound Ca(2+) and Zn(2+) from the Naja naja venom has been studied further for its anticoagulant property. The molecular mass by MALDI-TOF mass spectrometry was 67.81 kDa. The NN-PF3 exhibited fibrin(ogen)olytic activity. In addition to fibrinogen, NN-PF3 hydrolyzed blood and plasma clot with the later hydrolyzed about one fold higher. The alpha polymer of fibrin was preferentially hydrolyzed over the alpha chain but the beta chain and gamma-gamma dimer remained untouched. It was devoid of plasminogen activation property. It prolonged the activated partial thromboplastin time, prothrombin time and the thrombin clotting time of citrated human plasma. It did not affect the thrombin activity. In mice, defibrinogentaion, prolonged bleeding time (P < 0.01) and reduced fibrinogen level were observed following intravenous injection. Human plasma or alpha2-macroglobulin did not, but the polyvalent anti-venom inhibited the NN-PF3 activity. In contrast to most snake venom metalloproteases, it did not degrade extra cellular matrix proteins.
从眼镜蛇毒液中提取的具有结合 Ca(2+)和 Zn(2+)的高分子量非毒性金属蛋白酶 NN-PF3 ，其抗凝特性得到了进一步研究。MALDI-TOF 质谱法测定的分子质量为 67.81 kDa。NN-PF3 具有纤维蛋白（原）水解活性。除纤维蛋白原外，NN-PF3 还能水解血液和血浆凝块，后者的水解效率约高 1 倍。纤维蛋白的α聚合物优先被水解，而α链、β链和γ-γ二聚体则不受影响。它没有纤溶酶原激活活性。它延长了柠檬酸化人血浆的活化部分凝血活酶时间、凝血酶原时间和凝血酶凝固时间。它不影响凝血酶活性。在小鼠中，静脉注射后观察到纤维蛋白溶解、出血时间延长（P < 0.01）和纤维蛋白原水平降低。人血浆或α2-巨球蛋白没有，但多价抗蛇毒血清抑制了 NN-PF3 的活性。与大多数蛇毒金属蛋白酶不同，它不会降解细胞外基质蛋白。
