非洲爪蟾血清白蛋白的分离纯化及胰蛋白酶抑制活性  

Purification and Trypsin Inhibitory Activity of Xenopus laevis Serum Albumin

作　　者：张英霞[1] 李文辉[1] 张云[1] 

机构地区：[1]中国科学院昆明动物研究所毒素研究室

出　　处：《Zoological Research》2005年第6期622-626,共5页动物学研究（英文）

基　　金：国家自然科学基金资助项目(30170195;30470380);云南省自然科学基金资助项目(2003C0066M);中国科学院西部之光项目

摘　　要：通过凝胶过滤层析及两步阴离子交换层析,从非洲爪蟾(Xenopus laevis)的血清中获得了其68kDa的血清白蛋白。与大蹼铃蟾血清白蛋白相似,非洲爪蟾血清白蛋白也具有抑制胰蛋白酶的活性,但其抑制活力相对较低,180nmol/L的非洲爪蟾血清白蛋白能抑制84%的胰蛋白酶活性(30nmol/L)。经表面等离子共振法获得了其与胰蛋白酶的结合动力学常数,解离平衡常数KD=1.44×10-6mol/L。经Western blot分析发现,非洲爪蟾的皮肤中也分布有血清白蛋白。推测两栖类动物血清白蛋白具有的胰蛋白酶抑制活性可能是其抵御天敌捕食的一种防御措施。Frog albumin （XpA-serum） was purified from serum of Xenopus laevis by a combination of gel filtration and ion exchange chromatography steps. Like Bombina maxima albumin, XpA-serum exhibited trypsin inhibitory activity, which was lower than that of B. maxima albumin. XpA-serum at the concentration of 180 nM inhibited 84% activity of trypsin （30 nM）. The equilibrium dissociation constants （KD） is 1.44×10^-6 M as determined by Surface Plasmon Resonance, Western blot analysis revealed that XpA-serum was also distributed in the skin. It is deduced that serum albumin of amphibian possessing trypsin inhibitory activity can function directly or indirectly as a defensive substance against predators.

关 键 词：两栖类 非洲爪蟾 血清白蛋白 胰蛋白酶抑制剂 

分 类 号：Q51[生物学—生物化学]