Bovine serum albumin (BSA) is constituted of 582 amino acid
residues and based on the distribution of the disulphide bridges
and of the amino acid sequence, it seems possible to regard BSA
as composed of three homologous domains linked together. The
domains can all be subdivided into two sub-domains. As proposed
by Kragh Hansen (1981), there are at least six binding regions and,
another characteristic feature of albumin–ligand interactions, one
or two high affinity binding sites (primary sites) and a number of
sites with lower affinity.