Isolation and functional characterization of a new myotoxic acidic phospholipase A(2) from Bothrops pauloensis snake venom.

This article reports the purification procedure and the biochemical/functional characterization of Bp-PLA(2), a new myotoxic acidic phospholipase A(2) from Bothrops pauloensis snake venom. It was highly purified through three chromatographic steps (ion-exchange on CM-Sepharose, hydrophobic chromatography on Phenyl-Sepharose and RP-HPLC on a C8 column). Bp-PLA(2) is a single-chain protein of 15.8kDa and pI 4.3. Its N-terminal sequence revealed a high homology with other Asp49 acidic PLA(2)s from snake venoms. Its specific activity was 585.3U/mg. It displayed a high indirect hemolytic activity and inhibited platelet aggregation induced by collagen or ADP. It also induced in vivo edema and myotoxicity. Pretreatment of Bp-PLA(2) with BPB reduced the enzymatic activity, the inhibitory action on platelet aggregation and myotoxicity in vitro. Morphological analyses indicated that Bp-PLA(2) induced an intense edema, with visible leukocyte infiltrate and damaged muscle cells 24h after injection. Acidic myotoxic PLA(2)s from Bothrops snake venoms are still not extensively explored and knowledge of their structural and functional features will contribute for a better understanding of their action mechanism regarding enzymatic and toxic activities.