【摘要】 从天然中药材黄连中提取分离并精制得到盐酸小檗碱 ( BC) ,采用 UV光谱和荧光光谱 ( FS)研究其与牛血清白蛋白 ( BSA)的相互作用 ,解释了 BC导致 BSA的荧光发射光谱峰裂分的现象 ,其二重峰分别归属于色氨酸及酪氨酸残基 .结果表明 ,静态猝灭和非辐射能量转移是导致 BC对 BSA荧光猝灭的两大原因 ,BC与 BSA的表观结合常数 KA 为 8.66× 1 0 4 L/mol( 3 0℃ )和 8.72× 1 0 4 L/mol( 3 7℃ ) ,BC在 BSA分子上的结合位点数为 ( 3 .1± 0 .2 ) . BC与 BSA分子中荧光性氨基酸残基之间的距离为 3 .75 nm ( 3 0℃ )和 3 .62 nm( 3 7℃ ) ,表明 BC的部分片段能够插入 BSA分子内部 .热力学函数计算结果表明 ,该作用过程是一个熵增加、Gibbs自由能降低的自发超分子作用过程 ,并由此推断 BC与 BSA之间以疏水相互作用为主 .更多还原

【Abstract】 The interaction between bovine serum albumin(BSA) and berberine chloride(BC) extracted and purified from coptis chinensis franch was studied by using UV and fluorescence spectroscopy. The phenomenon that fluorescence spectra of BSA splitted and shifted from a simple peak to double peaks in the presence of BC was explained, and the double peaks responding to tyrosine and tryptophan residues respectively was prospected. Fluorescence quenching was thought to be deduced by combining static quenching with nonradiative energy transfer. The values of the apparent association constant(K A) at 30 ℃ and 37 ℃ are 8.66×104 L·mol -1 and 8.72×104 L·mol -1 respectively, and the binding sites of BC molecules on BSA(n) are (3.1±0.2). The stereo-distance(r) between BC and fluorescent amino acid residues of the BSA is 3.75 nm at 30 ℃ and 3.62 nm at 37 ℃, which affirms that part of BC segments have inserted into the hydrophobic pockets of BSA. Binding BC to BSA is a spontaneous supramolecular interaction in which entropy increases and Gibbs free energy decreases, and the main driving force of the above interaction is hydrophobic force.更多还原