摘要
The binding of kaempferol-3,7-α-L-rhamnopyranoside （KRR） with bovine serum albumin （BSA） was investi- gated by different spectroscopic methods under simulative physiological conditions. Analysis of fluorescence quenching data of BSA by KRR at different temperatures using Stern-Volmer methods revealed the formation of a ground state KRR-BSA complex with moderate binding constant of the order 10^4 Lomol-1. The existence of some metal ions could weaken the binding of KRR on BSA. The changes in the van＇t Hoff enthalpy （△H0） and entropy （△S0） of the interaction were estimated to be --26.53 kJ.mol-1 and 3.33 J.mol-l.K-1 and both hydrophobic and electrostatic forces contributed to stabilizing the BSA-KRR complex. According to the F6ster theory of non-radiation energy transfer, the distance r between the donor （BSA） and the acceptor （KRR） was obtained （r= 2.83 nm）. Site marker competitive experiments showed that KRR could bind to Site I of BSA. In addition, synchronous fluorescence, UV-Vis absorption and circular dichroism （CD） results indicated that the KRR binding could cause conformational changes of BSA.
The binding of kaempferol-3,7-α-L-rhamnopyranoside （KRR） with bovine serum albumin （BSA） was investi- gated by different spectroscopic methods under simulative physiological conditions. Analysis of fluorescence quenching data of BSA by KRR at different temperatures using Stern-Volmer methods revealed the formation of a ground state KRR-BSA complex with moderate binding constant of the order 10^4 Lomol-1. The existence of some metal ions could weaken the binding of KRR on BSA. The changes in the van＇t Hoff enthalpy （△H0） and entropy （△S0） of the interaction were estimated to be --26.53 kJ.mol-1 and 3.33 J.mol-l.K-1 and both hydrophobic and electrostatic forces contributed to stabilizing the BSA-KRR complex. According to the F6ster theory of non-radiation energy transfer, the distance r between the donor （BSA） and the acceptor （KRR） was obtained （r= 2.83 nm）. Site marker competitive experiments showed that KRR could bind to Site I of BSA. In addition, synchronous fluorescence, UV-Vis absorption and circular dichroism （CD） results indicated that the KRR binding could cause conformational changes of BSA.
基金
This work was supported by National Natural Science Foundation of China （Nos. 21061002, 20861002）, Guangxi Natural Science Foundation of China （Nos. 2010GXNSFF013001, 2011GXNSFC018009）.
