Multispectroscopic studies on the interaction of 2-tert-butylhydroquinone (TBHQ), a food additive, with bovine serum albumin

The interaction of 2-tert-butylhydroquinone (TBHQ) and bovine serum albumin (BSA) was investigated by spectrophotometry, spectrofluorimetry, circular dichroism (CD) and FT-IR techniques. The experimental results indicated that the quenching mechanism of BSA by TBHQ was a static procedure. Various binding parameters were evaluated. The negative value of ΔH, positive value of ΔS and the negative value of ΔG indicated that hydrophobic and hydrogen bonding interactions play major roles in the binding of TBHQ and BSA. Based on Forster’s theory of non-radiation energy transfer, the binding distance, r, between the donor (BSA) and acceptor (TBHQ) was evaluated. The results of CD, UV–vis and FT-IR spectroscopy showed that the binding of TBHQ to BSA induced conformational changes in BSA.