Fortes-Dias C L, Jannotti M L, Franco F J, Magalhães A, Diniz C R
Centro de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Belo Horizonte, Minas Gerais, Brazil.
Toxicon. 1999 Dec;37(12):1747-59. doi: 10.1016/s0041-0101(99)00116-6.
A phospholipase A2 inhibitor has been previously purified and cloned from the blood plasma of the South American rattlesnake, Crotalus durissus terrificus. This inhibitor, named CNF for Crotalus neutralizing factor, interacts with crotoxin, the main neurotoxin from C. d. terrificus venom, abolishing its phospholipase A2 activity. Crotoxin is a heterodimer of an acidic subunit (CA) and a basic phospholipase A2 (CB). CNF acts by forming a stable non-toxic complex with CB, replacing CA in the toxic CA-CB of crotoxin. In the present investigation, we have shown that CNF has a broader specificity. It is able to inhibit the PLA2 activity of the whole venom from the bushmaster snake (Lachesis muta muta), a species evolutionary related to Crotalus. Inhibition experiments have been carried out with four PLA2 active components isolated from L. m. muta venom, one basic and three acidic ones. CNF inhibition is not restricted to the basic PLA2, but extended to the three acidic forms as well.
一种磷脂酶A2抑制剂先前已从南美响尾蛇（Crotalus durissus terrificus）的血浆中纯化并克隆出来。这种抑制剂，名为响尾蛇中和因子（CNF），可与响尾蛇毒素（crotoxin）相互作用，响尾蛇毒素是C. d. terrificus毒液中的主要神经毒素，可消除其磷脂酶A2活性。响尾蛇毒素是一种由酸性亚基（CA）和碱性磷脂酶A2（CB）组成的异二聚体。CNF通过与CB形成稳定的无毒复合物发挥作用，在有毒的响尾蛇毒素CA-CB中取代CA。在本研究中，我们发现CNF具有更广泛的特异性。它能够抑制巨蝮蛇（Lachesis muta muta）整个毒液的PLA2活性，巨蝮蛇是一种与响尾蛇在进化上相关的物种。我们用从L. m. muta毒液中分离出的四种PLA2活性成分进行了抑制实验，一种碱性的和三种酸性的。CNF的抑制作用不仅限于碱性PLA2，也扩展到了三种酸性形式。
