Fluorometric studies on the binding of aflatoxin B1 to bovine serum albumin.

The quenching of dansylated BSA fluorescence by Aflatoxin B1 at the dansyl emission peak provided a useful method to study Aflatoxin B1 - BSA interaction, making evident one binding site with hydrophobic characteristics. The Ka = 4.0 X 10(4) M-1 at 18 degrees C could assing to this site a role in Aflatoxin B1 transport, but not in storage in the systemic circulation. Evidence supporting the presence of more binding sites, probably of similar characteristics as the former, was obtained from the study of the displacement of ANS bound to BSA by Aflatoxin B1, in spite of the fact that this interaction cannot be explained as a simple competition between ligands.