[Influence of rutin on conformation of serum albumin]

We studied the effect of the rutin on the conformation of bovine serum albumin (BSA) and human serum albumin (HSA) by synchronous fluorescence spectrum (Alambda = lambda(em) - lambda(ex) = 15 nm and deltalambda = lambda(em) -lambda(ex) = 60 nm) and circular dichroism spectra. The results showed that rutin had hardly effect on the serum protein conformation, but influenced the secondary structure of serum albumin (SA) molecule with the addition of rutin into BSA and HSA solution. The alpha-helix structure of BSA and HSA was decreased and the beta-sheet was increased with the increase in rutin concentration. At the same time, we studied the binding of rutin and bovine serum albumin (BSA) and human serum albumin (HSA) by electrochemistry under physiological condition. Cyclic voltammograms of rutin demonstrated a pair of well-reversible peaks in the solution of Tris-NaCl buffer at pH 7.38 (sweep rate: 50 mV x s(-1); a glassy carbon working electrode, a platinum auxiliary electrode, and a saturated calomel reference electrode). Both peak potentials of rutin were E(pc) = 0.103 2 V and E(pa) = 0.150 6 V, ipc : ipa = 1 : 1.2, the dispersion of peak potential was 47.4 mV (deltaE(prutin) = deltaE(pc) - E(pa) = 47.4 mV). In addition, with the addition of BSA and HSA into the rutin solution, both the reduction and oxidation currents decreased only at the peak potentials of rutin (BSA: E(pc) = 0.114 1 V, E(pa) = 0.168 5 V, ipc : ipa = 1 : 1.2; HSA: E(pc) = 0.114 2 V, E(pa) = 0.168 8 V, ipc : ipa= 1 : 1.1), the dispersions of peak potential were changed: for BSA deltaE(prutin) = [E(pc) - E(pa)] = 54.4 mV, and for HSA: deltaE(prutin) = [E(pc) - E(pa)] = 54.6 mV. The results showed that there was an interaction of rutin with BSA and HSA, forming a kind of nonelectroactive supramolecular complex, and indicated that rutin could be deposited and transported by serum protein in vivo.