A prothrombin activator from Bothrops erythromelas (jararaca-da-seca) snake venom: characterization and molecular cloning

• Autor(a) principal: Silva, Márcia B.
• Data de Publicação: 2003
• Outros Autores: Schattner, Mirta, Ramos, Celso RR, Junqueira-de-Azevedo, Inácio LM, Guarnieri, Míriam C., Lazzari, Maria A., Sampaio, Claudio Augusto Machado [UNIFESP], Pozner, Roberto G., Ventura, Janaína S., Ho, Paulo L., Chudzinski-Tavassi, Ana M.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNIFESP
• Texto Completo: http://repositorio.unifesp.br/handle/11600/27076; http://dx.doi.org/10.1042/BJ20020449
• topic: berythractivase; coagulation; haemostasis; metalloproteinases; thrombosis

A novel prothrombin activator enzyme, which we have named 'berythractivase', was isolated from Bothrops erythromelas (jararaca-da-seca) snake venom. Berythractivase was purified by a single cation-exchange-chromatography step on a Resource S (Amersham Biosciences) column. the overall purification (31-fold) indicates that berythractivase comprises about 5% of the crude venom. It is a single-chain protein with a molecular mass of 78 kDa. SDS/PAGE of prothrombin after activation by berythractivase showed fragment patterns similar to those generated by group A prothrombin activators, which convert prothrombin into meizothrombin, independent of the prothrombinase complex. Chelating agents, such as EDTA and o-phenanthroline, rapidly inhibited the enzymic activity of berythractivase, like a typical metalloproteinase. Human fibrinogen Aalpha-chain was slowly digested only. after longer incubation with berythractivase, and no effect on the beta- or gamma-chains was observed. Berythractivase was also capable of triggering endothelial proinflammatory and procoagulant cell responses. von Willebrand factor-was released, and the surface expression of both intracellular adhesion molecule-1 and E-selectin was up-regulated by berythractivase in cultured human umbilical-vein endothelial cells. the complete berythractivase cDNA was cloned from a B. erythromelas venom-gland cDNA library. the cDNA sequence possesses 2330 bp and encodes a preproprotein with significant sequence similarity to many other mature metalloproteinases reported from snake venoms. Berythractivase contains metalloproteinase, desintegrin-like and cysteine-rich domains. However, berythractivase did not elicit any haemorrhagic response. These results show that, although the primary structure of berythractivase is related to that of snake-venom haemorrhagic metalloproteinases and functionally similar to group A prothrombin activators, it is a prothrombin activator devoid of haemorrhagic activity. This is a feature not observed for most of the snake venom metalloproteinases, including the group A prothrombin activators.