Purification, characterization and cDNA cloning of an analgesic peptide from the Chinese scorpion Buthus martensii Karsch (BmK AGP-SYPU2).

In this study an analgesic peptide was purified through five continuous chromatographic steps. The mouse twisting model test was used to identify the target peptides in every separation step. The purified BmK AGP-SYPU2 was further qualified by Reverse Phase-High Performance Liquid Chromatography and High Performance Capillary Electrophoresis. The molecular weight, isoelectric point, and N-terminal sequence of the purified peptide were determined. Based on the N-terminal sequence, the cDNA was cloned by rapid amplification of the cDNA ends from the cDNA pool of scorpion glands. Sequence determination showed that the mature BmK AGP-SYPU2 peptide is composed of 66 amino acid residues, and BmK AGP-SYPU2 is identical to BmK alpha2 (GenBank Acc. No. AF288608) and BmK alphaTX11 (GenBank Acc. No. AF155364). We report herein a purification procedure that yields substantial amounts of natural BmK AGP-SYPU2 with high analgesic activity.