Study on the interaction of 6-thioguanine with bovine serum albumin by spectroscopic techniques

The interaction of 6-thioguanine (6-TG) and bovine serum albumin (BSA) was investigated by UV–Vis absorption, circular dichroism (CD) spectra and florescence spectroscopy. The experimental results indicated that the quenching mechanism of BSA by 6-TG was a static quenching procedure. Various binding parameters have been evaluated. ΔH0, ΔG0 and ΔS0, indicated that hydrophobic forces played a major role when 6-TG interacted with BSA. Based on the Forster’s theory of non-radiation energy transfer, the binding distance, r between the donor (BSA) and acceptor (6-TG) was evaluated. CD spectral results showed that the binding of 6-TG to BSA induced conformational changes in BSA.