【摘要】 根据徐洵等人的分离方法,我们从皖南山区尖吻蝮蛇蛇毒中得到出血毒素Ⅰ(AaH-1),它的萤光激发峰在284nm,发射峰在350nm,表现出Trp残基的萤光光谱。AaH-1的萤光强度和峰位随pH值的升高而增强且红移,在pH5～6萤光强度出现跃增,活性从无到有。pH7～9萤光强度稳定,出血活性的变化规律与此相似。升温到50℃以上其萤光强度急骤下降,并失活。一定浓度的SDS,EDTA均使AaH-1的萤光强度下降,出血活性也减弱。表明能改变AaH-1的pH环境、构象或使之变性的因素都能使它的萤光强度和出血活性同时发生相应的改变。AaH-1的萤光能分别被Ⅰ~-和丙烯酰胺碰撞淬灭,从萤光峰位和丙烯酰胺淬灭常数,可见Trp残基处于这些淬灭剂可以作用的位置。NBS能氧化AaH-1的Trp残基的吲哚环,而使Trp残基的萤光淬灭,致使AaH-1的活性也相应地减弱,说明Trp残基与出血活性有关。更多还原

【Abstract】 Using the method of Xu Xun et al,we have obtained hemorrhagin-1(AaH-1)from Agkistrodon acutus venom.Its emission and excitation maxima are at 350nmand 284nm respectively.The emission maximum shifts to longer wavelengths as the pH increases.Theintensity of ehe emission is sensitive to pH,SDS,EDTA and temperature.Thehemorrhagic activity of AaH-1 under these conditions show corresponding changes.The fluorescence of AaH-1 is quenched by I~-,acrylamide and N-bromosuccini-mide(NBS).Reaction of AaH-1 with NBS reduced the hemorrhagic activity ofAaH-1.From these results we suggest that the Trp residue in AaH-1 is situated Whereit could be acted upon by these factors and it is possible that this residue plays arole in the manifestation of hemorrhagic activity.更多还原