【摘要】 在研究癌变过程CPS₁^*活性降低的机制中,我们由大鼠肝分离提纯了CPS₁。方法是用去污剂十六烷基三甲基溴化铵从大鼠肝线粒体分离CPS₁,经过硫酸铵分步沉淀以及QAE-Sephadex A-50柱层析,得到聚丙烯酰胺凝胶电泳均一的CPS₁制剂,可与OCT 完全分开。由纯化的CPS₁制备的单价抗血清可以完全抑制大鼠肝及肝癌的CPS₁活性。免疫化学定量滴定证明肝癌、癌前肝及新生鼠肝CPS₁活性的变化,系由于相应酶蛋白量的改变,在其免疫化学性质上未发现有质的差异。更多还原

【Abstract】 In connection with studies on the mechanism of the decrease in CPS₁ activity inrat liver during carcinogenesis,we have isolated and purified CPS₁ from mitocho-ndria of rat liver by means of cetyl trimethylammonium bromide treatment,ammo-nium sulfate fractional precipitation and QAE-sephadex chromatography.By thisprocedure CPS₁ could be completely separated from OCT,another mitochondrial en-zyme involved in the urea cycle.The purified preparation of CPS₁ was shown to behomogeneous in polyacrylamide gel electrophoresis.The monospecific antiserumproduced in a rabbit from the purified CPS₁ could completely inhibit CPS₁ in bothnormal liver and hepatoma induced by diethylnitrosamine.Quantitative immunolo-gical titration indicated that the decrease in CPS₁ activities in hepatoma,diethylni-trosamine-fed liver and neonatal liver was due to decrease in the amount of enzymeprotein,without significant alteration in the immunologioal properties of CPS₁ fromthese different tissues.更多还原