中文摘要：

牛血清白蛋白在不同pH的溶液中存在N（Native，pH～7．0），B（Basic，pH～9．0），E（Expanded，pH3．5以下）等几种结构形态．用光谱技术研究了染料甲基（Methyl red，MR）和BSA的结合机理，研究了MK和BSA在不同pH的三酸缓冲溶液中的结构和构象变化，荧光猝灭方法测得两者在pH3．0，4．9，7．0，9．0溶液中结合常数分别为7．544×10^5L／mol，7．594×10^5L／mol，4．728×10^5L／mol，4．880×10^5L／mol；结合位点数分别为17．89，0．9783，3．079，8．865．同步荧光显示MK加入对Tyr残基微环境没有影响，但对Trp残基产生微扰，使其最大发射波长发生蓝移．图5，表1，参20．

英文摘要：

Bovine serum Albumin （BSA） is known to exist as N （Native, pH～7.0）, B （Basic, pH～9.0）, and E （Expanded, pH〈3.5） isomeric forms in the solution of different pH. The reaction mechanism between a dye （Methyl Red） and BSA was investigated by the fluorescence spectra. The structure and conformations of MR and BSA were studied in the Britton-Robison buffer solution. To elucidate MR binding behavior of BSA , the binding constant （KA） of MR with these eonformational state of BSA in the solution of pH3.0,4.9,7.0,9.0 by fluorescence quenching were 7.544 ×10^5 L/mol, 7.594 × 10^5 L/mol, 4.728 × 10^5 L/mol and 4.880 × 10^5 L/mol and the number binding sites （n） were 17.89,0.9783,3.079 and 8.865, respectively. The results show that the synchronous fluorescence spectra of Trp have blue shift and are quenched in the presence of MR. While without obvious shift to Tyr, the fluorescence intensity of Tyr decreased when the concentration of MR is lower. 5figs., 1tab., 20refs.