[Interaction between bovine serum albumin and umbelliferone with/without metal ions of Cu2+ or Zn2+].
The interaction between bovine serum albumin (BSA) a nd umbelliferone, an active component of Chinese herbs, with or without metal ions was investigated using fluorescence spectroscopy (FS) and UV. The experimental results showed that the umbelliferone molecules inserted into the hydrophobic pockets of BSA and quenched the intrinsic fluorescence of BSA by forming umbelliferone-BSA complex. The mechanism of fluorescence quenching was confirmed combining by both static quenching and nonradiative energy transferring. It was discovered that the apparent association constant (K(A)) increases in the presence of Cu2+ and Zn2+, whereas the spatial-distance (r) between umbelliferone molecule and fluorescent amino acid residues of the BSA and the binding sites (n) of umbelliferone molecules on BSA have no obviously change. Binding of umbelliferone molecules to BSA was a spontaneous supramolecular interaction in which entropy increased and Gibbs free energy decreaed. The interaction of the umbelliferone-BSA was driven mainly by electrostatic force which was enhanced by Cu2+ and Zn2+, thus the contribution of AH to AG increased in the presence of metal ions.
Liu
Xue-feng
XF
School of Chemical and Material Engineering, Southern Yangtze University, Wuxi 214036, China.
Xia
Yong-mei
YM
Fang
Yun
Y
Zou
Lu
L
Liu
Ling-ling
LL
D000465:Algorithms; D000818:Animals; D002417:Cattle; D003300:Copper / Q000737:chemistry* / Q000378:metabolism; D004735:Energy Transfer; D005453:Fluorescence; D007700:Kinetics; D008956:Models, Chemical; D011485:Protein Binding; D012710:Serum Albumin, Bovine / Q000737:chemistry* / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D055672:Static Electricity; D013816:Thermodynamics; D014468:Umbelliferones / Q000737:chemistry* / Q000378:metabolism; D015032:Zinc / Q000737:chemistry* / Q000378:metabolism
D014468:Umbelliferones; D012710:Serum Albumin, Bovine; C031477:7-hydroxycoumarin; D003300:Copper; D015032:Zinc