Nagata R, Kawachi E, Hashimoto Y, Shudo K
Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
Biochem Biophys Res Commun. 1993 Mar 15;191(2):543-9. doi: 10.1006/bbrc.1993.1252.
We have found that a synthetic urea derivative, N-(2-chloro-4-pyridyl)-N'-phenylurea (4PU30, forchlorfenuron), has even higher cytokinin activity than N6-benzyladenine (BA). Using [3H]4PU30 (2.83 TBq/mmol) as a probe, we confirmed chromatographically the presence of a high-affinity cytokinin-specific binding protein (CSBP) in whole-cell extract from etiolated mung bean seedlings. The apparent molecular weight of CSBP was estimated to be 21 kDa. The association constants (Ka's) of CSBP for 4PU30 and BA were calculated to be 4 x 10(10) M-1 and 3 x 10(9) M-1, respectively. Various active cytokinins showed mutually competitive binding to CSBP, and their affinities for CSBP corresponded well to their cytokinin activities at the tissue level.
我们发现一种合成尿素衍生物，N-(2-氯-4-吡啶基)-N'-苯基脲（4PU30，氯吡脲），其细胞分裂素活性甚至高于N6-苄基腺嘌呤（BA）。使用[3H]4PU30（2.83 TBq/mmol）作为探针，我们通过色谱法证实了黄化绿豆幼苗全细胞提取物中存在一种高亲和力的细胞分裂素特异性结合蛋白（CSBP）。CSBP的表观分子量估计为21 kDa。CSBP对4PU30和BA的缔合常数（Ka）分别计算为4×10(10) M-1和3×10(9) M-1。各种活性细胞分裂素对CSBP表现出相互竞争结合，并且它们对CSBP的亲和力与它们在组织水平的细胞分裂素活性很好地对应。
