Isolation and characterization of toxic proteins from the venom of the Brazilian scorpion Tityus serrulatus.

Through gel filtration on Sephadex G-25 and chromatography on CM-cellulose-52 five toxic proteins, electrophoretically pure, were isolated from the venom of the Brazilian scorpion Tityus serrulatus and partially characterized, as follows: 1. Toxin T1 VIII, with 61 amino acid residues, mol. wt 6675 and amino terminal sequence Lys-Glx-Gly-Tyr-Leu-Met-Asx-His-Glx-Gly-Cys-Lys-; 2. Toxin T1VI with amino acid residues, mol. wt. 7549 and amino terminal sequence Gly-His-Phe-Gly-Lys; 3. Toxin T2III(I), with 63 amino acid residues, mol. wt. 7216 and amino terminal sequence Lys-Lys-Asx-Gly-Tyr-Pro-Val-Cys-Cys-Ser-; 4. Toxin T2IV, which is apparently identical to toxin T1VIII above, since it showed the same elution volume in chromatography on CM-cellulose-52, the same N-terminal Lys and the same electrophoretic mobility as T1VIII; 5. Toxin T1IV, a not previously described toxin from the venom of T. serrulatus, with 45 amino acid residues, mol. wt. 5188 and amino terminal sequence Lys-Glx-Gly-Tyr-Leu-, identical to the first five residues of T1VIII, although with a lower molecular weight. The pharmacological study of T1VIII in guinea pig vas deferens showed a pre-junctional sensitizing action, evidenced by a decrease of the dose-response curves to adrenaline and acetylcholine, with no increase of the maximum. This effect may be due to the liberation of noradrenaline.