【摘要】 人血清白蛋(HSA)在2 96nm的光激发下能发射35 0nm的荧光(即λex=2 96 ,λem =35 0nm)。当HSA中加入适量的维生素B6 (B6 )后,HSA的荧光被部分猝灭,从τ0 (不加B6 时HSA的荧光寿命———分子激发态的寿命)与τi (加入B6 后的寿命)相等(近似)得知这种猝灭是静态猝灭。根据理论,可求出HSA与B6 间的结合常数K =2 6 7×10 4 L·mol- 1 。又从实验上可观察到HSA (它的激发态)可向B6 转移能量,由此可求出HSA和B6 间的临界距离R0 =1 872nm。测定了HSA和(HSA +B6 )的园二色(CD)谱,发现所测得的CD谱都很相似(基本上是一样的)。从测得的[θ]值可以算出各个样品所含的四种结构(α螺旋、β折叠片、β卷角,无规卷曲)的百分含量也大体相同。更多还原

【Abstract】 The Human Serum Albumin（HSA）can emit fluorescence（λ em=350 nm）unde r irradiation of ultraviolet light（λ ex=296 nm）. After the vitamin B ₆（B₆）was added into HSA solution the fluorescence of HSA was quenched part ially. This quenching was static quenching owing to the fact that τ₀（fl uorescence life time （life time of the molecule excitation state） of HSA without B₆） equaled to τ_i（fluorescence life time of HSA with B₆）. The for mation constant K between HSA and B₆ was observed from the experiment, and then the binding distance R₀ was determined（R₀=1.872 nm）. The C D spectra of samples （HSA, =1×10 -5 mol·L -1, HSA+B₆, =5×10 -8, 1.5×10 -7, 2.5×10 -7, 3.5×10 -7 , 4.5×10 -7 mol·L -1） were measured, and all CD spectra were almost the same. From values, the contents（percent content）of four structure（α-Helix, β-Pleated, β-corner, and Randon wind ）of samples can be calculated, and we find that all samples contain almost the same structure contents.更多还原