Xia Xuechun, Hou Fajian, Li Jie, Ke Yibao, Nie Huiling
Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
J Biochem. 2006 Apr;139(4):725-31. doi: 10.1093/jb/mvj081.
Trichosanthin is the active protein component in the Chinese herb Trichosanthes kirilowi, which has distinct pharmacological properties. The cytotoxicity of trichosanthin was demonstrated by its selective inhibition of various choriocarcinoma cells. When Jar cells were treated with trichosanthin, the influx of calcium into the cells was observed by confocal laser scanning microscopy. When the distribution of trichosanthin-binding proteins on Jar cells was studied, two classes of binding sites for trichosanthin were shown by radioligand binding assay. Furthermore, the cytoplasmic membrane of Jar cells was biotinylated and the trichosanthin-binding proteins were isolated with trichosanthin-coupled Sepharose beads. Two protein bands with molecular masses of about 50 kDa and 60 kDa were revealed, further characterization of which should shed light on the mechanism of the selective cytotoxicity of trichosanthin to Jar cells.
天花粉蛋白是中药栝楼中的活性蛋白成分，具有独特的药理特性。天花粉蛋白的细胞毒性表现为对各种绒毛膜癌细胞的选择性抑制。用天花粉蛋白处理Jar细胞时，通过共聚焦激光扫描显微镜观察到钙离子流入细胞。研究Jar细胞上天花粉蛋白结合蛋白的分布时，放射性配体结合试验显示出两类天花粉蛋白结合位点。此外，对Jar细胞的细胞质膜进行生物素化处理，并用与天花粉蛋白偶联的琼脂糖珠分离天花粉蛋白结合蛋白。发现了两条分子量约为50 kDa和60 kDa的蛋白条带，对其进一步表征应有助于阐明天花粉蛋白对Jar细胞选择性细胞毒性的机制。
