Isolation and characterization of the recombinant human α-fetoprotein fragment corresponding to the C-terminal structural domain

摘要

Alpha-fetoprotein (AFP) is the major human oncofetal protein. The receptor of AFP is expressed by cells of various tumors and is not produced by normal cells of the adult body. In an AFP molecule, the site of binding to its receptor is localized in the third domain. The conjugates of the natural AFP with a variety of cytostatics inhibited the growth of tumor cells in vivo and in vitro. The C-terminal fragment of AFP (amino acid residues 404-595 of the full-length protein) was cloned and expressed in cells of the Escherichia coli strain BL21(DE3). The yield of the protein was no less than 150 mg/l. A highly efficient method of its isolation and renaturation was developed so that the yield of the protein was no less than 50% with a purity of about 93%. The renatured third domain of AFP bound specifically to and penetrated into cells having the AFP receptor. The recombinant third domain of AFP can be used as a carrier for targeted drug delivery to tumor cells.