亲和层析法分离腺苷结合蛋白质

本文报告一种新的腺苷亲和层析凝胶的合成方法。利用这种凝胶可从大鼠心脏、肝脏及小牛主动脉平滑肌的水溶部份分离出几种腺苷结合蛋白质,其亚基分子量(据SDS-PAGE)分别为35,000、37,000、46,000、43,000及15,300Dal。现已证明,35,000Dal蛋白质是乳酸脱氢酶及苹果酸脱氢酶,43,000Dal蛋白质是腺苷激酶,46,000Dal蛋白质可能是S-腺苷同型半胱氨酸水解酶。15,000Dal蛋白质前人未有报道。它对腺苷具有高度特导性和亲和力,推测是腺苷的细胞内受体和/或载体。测定了这种低分子量腺苷结合蛋白质的氨基酸组成及某些物理常数:pI=6.5;沉降系数2.42S,微分比容0.727cm~3/g,与腺苷复合物的解离常数K_D=2.3μM。

ISOLATION OF THE ADENOSINE BINDING PROTEINS BY AFFINITY CHROMATOGRAPHY

A new type of adenosine affinity gel has been synthesized.Several adenosine binding proteins have been isolated from the soluble fractions of rat heart,rat liver and calf aortic smooth muscle by affinity chromatography using the gel.The adenosine binding proteins have subunits with molecular weight of 35,000,37,000,46,000,43,000 and 15,300 respectively.The 35,000 Dal protein has been identified as lactate dehydrogenase and malate dehydrogenase,the 43,000 Dal protein is adenosine kinase,and the 40,000 Dal protein might be S-adenosylhomocysteine hy-drolase.The 15,300 Dal protein has not been reported previously and possibly is an intracellular receptor and/or carrier for adenosine.The new adenosine binding protein has a sedimentation coefficient of 2.42s,a KD for adenosine of 2.3μM,and a pI of 6.5.The amino acid composition of the protein is presented.The amino acid composition yields a partial specific volume of 0.727 cm3.g-1.