BOTHROPS-JARARACA SNAKES PRODUCE SEVERAL BOTHROJARACIN ISOFORMS FOLLOWING AN INDIVIDUAL PATTERN

More than one isoform of bothrojaracin (BJC), a potent and specific th rombin inhibitor isolated from Bothrops jararaca venom, has been found in individual venoms collected from adult snakes. Variations in snake venom composition have previously been associated with factors such a s age, sex, geographic origin, season of the year and diet. In order t o obtain further information concerning individual patterns of express ion of BJC isoforms, we have analyzed five individual Bothrops jararac a snake venoms collected at the same time from adult female snakes fro m the same geographic region. As expected, crude venoms showed a simil ar migration pattern on SDS-PAGE. BJC was purified using a procedure w hich includes an affinity chromatography step (PPACK-thrombin Sepharos e). A slight variation in the amount of BJC obtained from individual v enom samples was noticed. Inhibition of thrombin-induced platelet aggr egation as well as migration pattern on SDS-PAGE (under reducing and n on-reducing conditions) and isoelectric focusing varied considerably a mong BJC samples from the five snakes. The amino-terminal sequences (r esidues 1-34) of individual BJC samples were compared with the sequenc e deduced from isolated cDNAs encoding alpha and beta chains of BJC. A high degree of homology was detected, although some residues differed from one sample to other. Altogether, data confirmed the heterogeneit y found for BJC purified from individual snakes. Thus, the results ind icate that: (1) individual specimens of Bothrops jararaca have differe nt patterns of BJC isoform expression; and (2) it seems that genetic f actors, at least in part, determine the variability found in BJC produ ction. (C) 1998 Elsevier Science Inc. All rights reserved.