Short sequences of high homology between the primary structures of alpha-fetoprotein and albumin

Several reports have shown a high percentage of homology between the primary structures of alpha-fetoprotein (AFP) and serum albumin (Alb). With the aid of a program which searches for all identical sequences, we compared the aminoacid sequence of AFP and Alb from several species. Two short pieces of very high homology were always present in all the AFPs and Albs studied, but in none of the other analyzed proteins. One is in Domain I (16 amino acids long) and the other in Domain III (17 residues long). The implications of this finding in relation to the function and evolution of AFP and Alb are discussed.