For the GBGT1 genes, the sequence of the same location is also highly conserved. However, the conserved sequence is GDFYYGGA(L/V)FGG, and the HA sequence in the GGTA1 and A3GALT2 transferases is replaced with GG in the transferases. The exceptions were found in macaque and cow (GDFYYGRAVFGG) genes. Ten amino acids are deleted just downstream of this sequence in cow, which explains why cow is Forssman-negative. The inactivity is also explained by the amino acid substitution of alanine to lysine (A268K) in the macaque gene. This finding is based on the results of the A268K in vitro mutagenized construct of human B transferases.