Homology between the primary structure of alpha-fetoprotein, deduced from a complete cDNA sequence, and serum albumin.

The entire DNA complementary to murine alpha-fetoprotein mRNA has been cloned in the plasmid vector pBR322 and its complete nucleotide sequence determined. The deduced amino acid sequence identifies a hydrophobic prepeptide of 19 amino acids and the complete primary structure of alpha-fetoprotein. Its structure reveals extensive homology to serum albumin and suggests that there are 15 disulphide bridges in the alpha-fetoprotein molecule, all at the same positions as those found in albumin. The AFP molecule can be organized into a three-domain structure almost identical to that of serum albumin, suggesting a common ancestral origin of the two proteins.