Circular dichroism study on effect of puerarin on the secondary structure of bovine serum albumin in the presence of copper ion

Effect of puerarin( PUE) on the secondary structure of bovine serum albumin( BSA) in the presence of copper ion was investigated by circular dichroism( CD) spectroscopy. The results indicated that BSA contained 56. 3% α-helix,26. 1% β-sheet,17. 6% turn and random in pH 7. 4 PBS buffer. The secondary structure of BSA was induced by PUE and Cu2 +-PUE. PUE caused increase in the content of α-helix and decrease in the content of β-sheet. Which shows that the interaction between PUE and BSA increases hydrophobic interactions, leading to that the peptide chain of BSA occurs contraction and rearrangement,and the conformation of BSA changs. Cu2 +-PUE caused decrease in the content of α-helix and increase in the content of β-sheet. Which shows that the interaction between Cu2 +-PUE and BSA increases coordinate interactions,leading to that the peptide chain of BSA occurs extension and rearrangement,and the conformation of BSA changes.