Isolation, purification, and N-terminal partial sequence of an antitumor peptide from the venom of the Chinese scorpion Buthus martensii Karsch.

An antitumor peptide (ANTP) was isolated and purified from the venom of the Chinese scorpion Buthus martensii Karsch. The purification procedure included gel filtration on Sephadex G-50 and Superdex 30 high resolution chromatography, Phenyl Sepharose 6 Fast Flow chromatography, and SP-Sepharose Fast Flow chromatography. Its homogeneity was demonstrated by size exclusion HPLC on TSK G2000 SW. The isoelectric point is more than 10 by pH 3-10 range isoelectric focusing. ANTP has a relative molecular mass of 6280, calculated from the measurement of 16.5% SDS-PAGE. The pharmacological tests showed that ANTP has antitumoral effects in the mouse S-180 fibrosarcoma model and Ehrlich ascites tumor model. Amino acid analysis suggested the ANTP is rich in glycine and does not have histidine and threonine. The sequence of the first 25 N-terminal residues is as follows: Val-Arg-Asp-Gly-Tyr-Ile-Ala-Asp-Asp-Lys-Asn-Cys-Ala-Tyr-Phe-Cys-Gly-Arg-Asn-Ala-Tyr-Cys-Asp-Asp-Glu.