THE IDENTITY OF THE BINDING-SITES OF BILE-SALTS ON BOVINE SERUM-ALBUMIN

The binding of hydroxy and keto bile salts to bovine serum albumin was studied using probes for the so-called site I, II, bilirubin and fatty acids. Lithocholate, cholanate-3-one and cholanate-3,6-dione produced an interference in the energy transfer process between the albumin-tryptophan residues and the fluorescence markers of sites I and II. The results showed that site II is the binding site for the bile salts on bovine serum albumin. The binding produced a conformational change at site I, bilirubin and fatty acid binding sites, suggesting that these sites may overlap with site II.