Table 3 shows the rate of hydrolyzes of angiotensin I, dynorphin1-13, neurotensin1-13 and bradykinin, by the B. jararaca venom. In this set of putative substrates, only bradykinin was not hydrolyzed by the BjV and a good cleavage of angiotensin I was observed. Dynorphin1-13 was also well hydrolyzed by the B. jararaca crude venom, followed by the neurotensin1-13 degradation. Table 3 also shows the cleavage points determined in angiotensin I and dynorphin1-13. As can be observed, Z-VAD-FMK in vivo angiotensin I presents one cleavage point between the residues Tyr–Ile, that was totally blocked

by PMSF and not affected by EDTA or 1,10-phenantroline. Moreover, the commercial serum produced www.selleckchem.com/products/Thiazovivin.html by the Butantan Institute was able to reduce only 44% of the hydrolysis of angiotensin I by BjV. Dynorphin1-13 presents two scissile bonds, between the residues Arg–Arg and Lys–Leu, that were principally blocked by PMSF (88%) and partially blocked by EDTA (28%), and 1,10-phenantroline (6%). Table 3 shows that the antibothropic serum was able to block 48% of the hydrolytic activity of

the venom on dynorphin A cleavage. Since the observation of angiotensin I cleavage is mainly due by serine peptidases and partially blocked by the antivenom, we decided to test the other four bothropic venoms used to make the immunization pool. The results obtained with the venoms used to compose the immunization pool, again showed the presence of a chymotrypsin-like activity in these venoms, although with distinct specific activities (Table 4). The cleavage points were unique between Tyr–Ile bonds (data not shown) and were determined by the internal standardization of the HPLC conditions using the BjV. The blocked effect of the antibothropic

serum was different for each old venom, showing variations in their composition. The angiotensin-I hydrolyzes by the venom from B. jararacussu and B. jararaca were only partially blocked by the commercial antivenom ( Table 4). In contrast, angiotensin I degradation was fully inhibited by using the antivenom when the venoms from B. moojeni and B. neuwiedi were used. Although it was proposed that B. jararaca and Bothrops neuwied should be included in the genus Bothropoides, and B. alternatus into genus Rhinocerophis, there is no clear consensus about the systematics of this group ( SBH, 2007). Since human envenomations involving these species are treated with the antibothropic serum, this study still considers these snake venoms as belonging to the genus Bothrops. The objective of the present study was to analyze the ability of the antivenom produced by the Butantan Institute, São Paulo, Brazil, to neutralize B. jararaca major venom toxins. A set of FRET peptides (Free Ressonance Energy Transfer) was studied using the BjV and site-directed inhibitors PMSF, EDTA and 1,10-phenanthroline.