Chatterjee A, Bhattacharya A K
Department of Biophysics, Banaras Hindu University, Varanasi, India.
Int J Radiat Biol Relat Stud Phys Chem Med. 1988 Jun;53(6):977-82. doi: 10.1080/09553008814551331.
The incorporation of [14C]adenine into the cyclic AMP fraction by whole cells of Escherichia coli B/r was taken as a measure of the in vivo adenylate cyclase activity. This activity was significantly inhibited by irradiation of the cells either with 60Co gamma-rays or with UV light from a germicidal lamp, suggesting inhibition of cyclic AMP synthesis. The incubation of cells after irradiation with lower doses (50-100 Gy) of gamma-rays produced a significant increase of in vivo adenylate cyclase activity, whereas there was no significant change after higher doses (150 Gy and above). Dark incubation of cells after irradiation with UV light (54 J m-2) led to recovery of enzyme activity to the level measured in unirradiated cells. Thus it appears that the catabolite repression of L-arabinose isomerase induced by UV light, as well as gamma-irradiation, is due to reduced cyclic AMP synthesis in irradiated cells.
将大肠杆菌B/r全细胞中[14C]腺嘌呤掺入环磷酸腺苷部分作为体内腺苷酸环化酶活性的一种衡量指标。用60Coγ射线或杀菌灯的紫外线照射细胞会显著抑制这种活性，这表明环磷酸腺苷的合成受到了抑制。用较低剂量（50 - 100 Gy）的γ射线照射细胞后进行孵育，体内腺苷酸环化酶活性显著增加，而较高剂量（150 Gy及以上）照射后则无显著变化。用紫外线（54 J m-2）照射细胞后进行暗孵育，酶活性恢复到未照射细胞所测水平。因此，似乎紫外线以及γ射线诱导的L - 阿拉伯糖异构酶的分解代谢物阻遏是由于照射细胞中环磷酸腺苷合成减少所致。
