Abstract: The open reading frame of GP29, a gene expressed only in the salivary glands of the fed adult tick H.asiaticum， was cloned into expression vector pGEX-4T-1. A novel protein of approximately 53 ku，being in agreement with that predicted from the translated cDNA sequence，was expressed by the Escherichia coli （BL21 strain）transformed with p29-pGEX-4T-1. The peptide mass mapping of the protein and the peptide sequencing of the “1381.7511 m/z” peptide suggested that the protein in the 53 ku band on SDS-PAGE was the GST-fusion protein expressed by the GP29 gene . Comparison of the sequence of the protein to that of other proteins in the Swiss PROT data base revealed no significant homology，indicating that it is a novel bioactive molecule.

Key words: H.asiaticum, gene GP₂₉, GSTfusion protein, the peptide mass, the peptide sequence