Isolation and Characterization of the Toxic Component of Enhydrina schistosa (Common Sea Snake) Venom

Abstract

Abstract The toxic component from the venom of the common sea snake (Enhydrina schistosa) was isolated by passage of the venom through a carboxymethyl cellulose column. The preparation, which was shown to be homogeneous by zonal electrophoresis, ultracentrifugation, isoelectric focusing, and gel filtration, had a median lethal dose 50% (LD50) toward mice of 0.044 µg per g of body weight. The molecular weight of the toxic protein, as determined by sedimentation velocity and diffusion experiments, was found to be 7200. The minimum molecular weight calculated from amino acid analysis was 7000. The isoelectric point, determined by isoelectric focusing, was 9.2. Although hyaluronidase, alkaline phosphatase, phosphodiesterase, phospholipase A, acetylcholinesterase, DNase, leucine amino peptidase, and clotting activity could all be detected in unfractionated venom; no enzymatic activity could be found in the purified toxin. The compound N-bromosuccinimide completely destroyed the toxicity of the preparation, which, under the conditions employed, strongly suggests that tryptophan is necessary for toxicity.