An insect excitatory toxin gene from Buthus martensii Karsch (BmKIT) was cloned into the expression vector, pET-28a. BmKIT was expressed as inclusion bodies in Escherichia coli BL21 (DE3) host cells. The authenticity of in vitro expressed protein was confirmed by Western blot. The inclusion body protein band in SDS-PAGE was excised and the protein, BmKIT, was extracted. Polyclonal antibodies to the purified protein were raised in rabbits. The antibody reacted specifically with the expressed BmKIT and was used to quantify its presence in transgenic cotton.