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    BE-I-PLA2, a novel acidic phospholipase A(2) from Bothrops erythromelas venom: Isolation, cloning and characterization as potent anti-platelet and inductor of prostaglandin I-2 release by endothelial cells
    (Elsevier B.V., 2006-07-28) Albuquerque Modesto, Jeanne Claine de; Spencer, Patrick J.; Fritzen, Marcio; Valenca, Renata C.; Oliva, Maria Luiza Vilela [UNIFESP]; Bezerra da Silva, Marcia; Chudzinski-Tavassi, Ana Marisa; Camargo Guarnieri, Miriam; Universidade Federal de Pernambuco (UFPE); Inst Butantan; IPEN; Universidade Federal de São Paulo (UNIFESP)
    A novel acidic Asp49 phospholipase A(2) was isolated from Bothrops erythromelas (jararaca malha-de-cascavel) snake venom by four chromatographic steps. BE-I-PLA2 present a molecular weight of 13,649.57 Da as estimated by mass spectrometry. N-terminal and four internal peptides were sequenced, covering around one-third of the complete toxin sequence. the complete BE-I-PLA2 cDNA was cloned from a B. erythromelas venom-gland cDNA library. the cDNA sequence possesses 457 bp and encodes a protein with significant sequence similarity to many other phospholipase A(2) from snake venoms. When tested in platelet rich plasma, the enzyme showed a potent inhibitory effect on aggregation induced by arachidonic acid and collagen, but not ADP. On the other hand, BE-I-PLA2 did not modify aggregation in washed platelet. Furthermore, no action of BE-I-PLA2 on the principal platelets receptors was observed. Chemical modification with p-bromophenacyl bromide abolished the enzymatic activity of BE-I-PLA2, but its anti-platelet activity was only partially inhibited. in human umbilical-cord veins endothelial cells, BE-I-PLA2 was neither apoptotic nor proliferative but stimulated endothelial cells to release prostaglandin I-2, suggesting an increase of its potential anti-platelet activity in vivo. Further studies are required in order to determine the exact mechanism of action of BE-I-PLA2 in the inhibition of platelet aggregation. (c) 2006 Elsevier Inc. All rights reserved.