Investigation of the interaction of alkyl sulphates with serum albumin using the thiocyanate radical ion (SCN)2.

Abstract

The reaction of the radical anion -(SCN)2-, produced during pulse radilysis of aqueous KCNS solutions, have been used to study the binding of a range of alkyl sulphates to bovine (BSA) and human (HSA) serum albumin. At neutral pH, -(SCN)2- reacts chiefly with trytophan residues. Approximately ten high-affinity binding sites are detectable for compounds of chain length greater than C7. The results are interpreted in terms of a model in which one hydrophobic region in the protein, containing the tryptophan residues, can accommodate the ten ligand molecules. Electrostatic interactions with positively-charged groups surrounding the hydrophobic area are also involved in binding.