Binding Peptide Screening and Potential Target Protein Identification of Trichosanthin

OBJECTIVE To screen binding peptides and identify potential target protein of trichosanthin (TCS) by homology analysis. METHODS TCS was used to pan against the fifteen peptide library and a random twelve peptide library by solid-phase screening， respectively. A series of positive clones that bind specifically to TCS were obtained after 4 rounds biopanning process， and the monoclonal phage ELISA was used to test the affinity between positive clones and TCS. The amino acid sequence of positive peptides was sequenced and homology analysis was performed to identify the potential target protein of TCS. RESULTS The yield and polyclonal phage ELISA showed that the panning was effective. Positive clones were picked by monoclonal ELISA and the displayed peptide sequence was identified by sequencing. Some proteins that had homology with registered proteins in PROSITE and BLAST were found. The potential target protein of TCS probably was protein kinase C. CONCLUSION Phage display random peptide library technology is a powerful method for exploring the target protein of traditional Chinese medicine ingredients. Protein kinase C probably is the target protein of TCS.