Zhang D C, Cao C X, Zhang C J, Zhou B N
Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing.
Sci China B. 1993 Jul;36(7):803-8.
Protein kinase C with a molecular weight of 82 kD has been purified to electrophoresis homogeneous from rat brain through a series of chromatography columns including DE-52, Sepharose G-200 and phenyl-Sepharose. The enzyme possessed autophosphorylation activity. Yuanhuacin A inhibited the 3H-phorbol-12, 13-dibutyrate (3H-PdBu) binding of PKC with an IC50 value of 1.48 +/- 0.28 x 10(-8) mol/L when the concentration of 3H-PdBu was 1.5 x 10(-9) mol/L (Ki = 1.2 x 10(-8) mol/L). Yuanhuacin A inhibited the PdBu-stimulated PKC activity in the catalysis of the phosphorylation of Histone III-S with an IC50 of 2.82 +/- 0.37 x 10(-9) mol/L (PdBu = 10(-6) mol/L), while it had no effect on the basal and Ca(2+)-stimulated PKC activity in the same assay system. This result suggests that Yuanhuacin A is a selective antagonist of the phorbol ester receptor in protein kinase C.
分子量为82kD的蛋白激酶C已通过包括DE - 52、琼脂糖凝胶G - 200和苯基琼脂糖在内的一系列色谱柱从大鼠脑中纯化至电泳纯。该酶具有自身磷酸化活性。当3H - 佛波醇 - 12,13 - 二丁酸酯（3H - PdBu）浓度为1.5×10(-9)mol/L时，芫花酯甲抑制蛋白激酶C与3H - PdBu的结合，IC50值为1.48±0.28×10(-8)mol/L（Ki = 1.2×10(-8)mol/L）。在组蛋白III - S磷酸化催化中，芫花酯甲抑制PdBu刺激的蛋白激酶C活性，IC50为2.82±0.37×10(-9)mol/L（PdBu = 10(-6)mol/L），而在相同测定系统中对基础和Ca(2+)刺激的蛋白激酶C活性无影响。该结果表明芫花酯甲是蛋白激酶C中佛波醇酯受体的选择性拮抗剂。
