【摘要】 用植物体内天然存在并具有很高活性的玉米素（ｔ－Ｚ）和异戊烯基腺苷（ｉＰＡ）作为配基，分别与Ｓｅｐｈａｒｏｓｅ－４Ｂ偶联，制成亲和吸附介质，分离、纯化菜豆（Ｐｈａｓｅｏｌｕｓ ｖｕｌｇａｒｉｓ）黄化幼苗下胚轴中的细胞分裂素结合蛋白。一种分子量为１５．５ ｋＤ（简称ＺＢＰ），只含一个多肽链；另一种分子量为１６５ ｋＤ（简称ＩＢＰ），含有两种亚基，分子量分别为４３ ｋＤ和４０ ｋＤ。对ＺＢＰ的结合活性进行了研究，发现ＺＢＰ与ｔ－Ｚ结合时的解离常数（Ｋｄ）为３．２×１０－ ７ ｍ ｏｌ／Ｌ。经计算，每个ＺＢＰ分子只有一个ｔ－Ｚ结合位点更多还原

【Abstract】 t Zeatin (t Z) and isopentenyladenosine (iPA) occur naturally as highly active plant cell division regulators.t Z Sepherose 4B and iPA Sepherose 4B affinity column were constructed to isolate and purify the cytokinin binding proteins from etiolated hypocotyl of Phaseolus vulgaris.Two kinds of cytokinin binding proteins were obtained.One was 15 5 kD in molecular weight (named ZBP) with only one peptide.The other (named IBP), 165 kD in molecular weight, contained two different subunits (40 kD and 43 kD respectively).The binding activity of ZBP was tested and the dissociation constant (Kd) was determined to be 3 2×10 -7 mol/L.There was one binding site for t Z in each molecule of ZBP.更多还原