大白鼠DNA拓扑异构酶Ⅰ生物学性质的研究

对大白鼠组织作DNA拓扑弄构酶Ⅰ(拓扑酶Ⅰ)活力测定,见酶活力出现在胚胎早期,在胚胎发育过程及出生后不同年龄期,酶活力基本稳定;几种成年大鼠组织的酶活力彼此无显著差异;肝细胞再生及癌变,酶活力亦无显著变化。

A STUDY ON BIOLOGICAL PROPERTIES OF RAT DNA TOPOISOMERASE I

DNA tepoisomerase I activities of rats are reported. Nuclei were isolated and purified from rat tissues, crude enzymes were extracted from the nuclei and specific activities of the enzymes were measured. The results showed that the DNA topoisomerase I activities were found in ten-day old embryonic tissues and the level of the activities maintained constant during embryonic development and different ages after birth. No significant difference of the enzyme activities was found among the different adult rat tissues including liver, brain, spleen, lung and kidney.These results indicated that the Top I gene was expressed early in embryonic stage and remained turning on during the later stages in different tissues throughout the adulthood. In the process of liver regeneration there was no significant change of the enzyme activity. Furthermore, the level of enzyme activity in DAB-induced rat hepatoma was the same as in normal liver.