Abstract: The recombinant plasmid containing towel gourd ACC synthase cDNA was successfully transformed into Escherichia coli BL21(DE3) and the ACC synthase expression was significantly induced by IPTG. The expressed protein exists in the form of inclusion bodies. The towel gourd ACC synthase was purified by abstersion and chromatography. SDS-PAGE analysis of the purified protein showed only one band with molecular mass of 55 000.　The optimum pH of the expressed towel gourd ACC synthase reaction is 8.5 and the K_m values of enzyme is 44 .2　μmol/L at pH　8.5.

Key words: towel gourd ACC synthase, inclusion bodies, protein purification