Investigation of the Interaction of Alkyl Sulphates with Serum Albumin Using the Thiocyanate Radical Ion ·(SCN)₂⁻

Summary

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 > 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.