Atividade conversora de angiotensina do muco epidérmico e peçonha do peixe-escorpião Scorpaena plumieri

Abstract

The venom of terrestrial animals is much more studied than that of marine animals, for factors such as the easiest access and the lowest lability of its active compounds. Thus, only a small part of what is known about venom is of marine origin. The Scorpaena plumieri is a venomous fish, typical of tropical Waters of Atlantic Ocean, which inhabits corals and shallow waters on rocky beaches, known in the northeast region of Brazil as scorpion fish, niquim-de-pedra, mamangava or beatriz, is a fish that has an inoculating apparatus not very well defined, composed of glands that extend through the anterolateral region of spicules present in the dorsal pelvic and anal fins. In its venom, several substances with biological activity have already been isolated, with activities similar to other fish of the family Scorpionidae. This venom has hemolytic, cytotoxic, inflammatory, cardiovascular and proteolytic activity, as well as integrin binding inhibitor. The fish's body is also abundantly covered by thick mucus. By testing these bodily fluids, we find in them the ability to process angiotensins. The venom of the S. plumieri scorpion fish was able to convert angiotensin I (Ang I) to angiotensin II and also to angiotensin I-7 (Ang (1-7)), and capable of converting angiotensin II (Ang II) into Ang (1-7). Epidermal mucus was able to convert Ang I into Ang II and Ang (1-7), but did not show activity against Ang II. The angiotensin converting enzyme inhibitor captopril was able to inhibit the conversion activity in both biological fluids, as well as the metal chelator EDTA. As for the serine protease inhibitor PMSF, it was not able to inhibit venom activity. Captopril was also not able to prevent the formation of Ang (1-7) from Ang I in the epidermal mucus, showing that there must be an enzyme that directly promotes the conversion of Ang I to Ang (1-7), without the need for prior conversion in Ang II. The most interesting activity, the angiotensin converting enzyme (ACE), was isolated in two sequential chromatographic steps, namely; gel filtration in S-100 and ion exchange with Mono Q. Isolated ACE behaved in the same way against inhibitors and substrate, Ang I, except for the ability to generate Ang (1-7). Animal venoms are complex mixtures of molecules with biological activity, and their study can both be seen as a way to better understand the effects of envenomation and open up possibilities for better treatment methods as well as for the discovery of activities that may have pharmacological utility, or help to undestand a metabolic pathway.