Takáts A, Binh V H, Bertók L
Frédéric Joliot-Curie National Research Institute for Radiobiology and Radiohygiene, Budapest, Hungary.
Acta Physiol Hung. 1990;76(4):265-72.
The role of oxidation of SH groups in the activity of adenylate cyclase and in radiosensitivity of the enzyme was investigated. Adenylate cyclase activity was measured in purified membrane preparation of 19 day old chicken embryo brains. N-ethyl-maleimide (NEM) and lead-acetate were used as SH inhibitors. Gamma irradiation was carried out with 60-Co source. NEM inhibition of adenylate cyclase was dose dependent and 50 per cent inhibition was observed at 40-50 microM NEM. Activity of adenylate cyclase was elevated at lower concentrations of lead-acetate (10 nM-100 microM) and was inhibited at higher concentrations (above 100 microM). The presence of 40 microM NEM did not alter the shape of lead acetate saturation curve of adenylate cyclase. Gamma irradiation in the dose range of 100-800 Gy elevated the adenylate cyclase activity measured in the presence of 5 mM NaF but did not alter the basal activity. Gamma irradiation did not have significant effect on NEM saturation of adenylate cyclase, while it altered slightly the lead acetate saturation curve.
研究了巯基氧化在腺苷酸环化酶活性及该酶放射敏感性中的作用。在19日龄鸡胚脑的纯化膜制剂中测定腺苷酸环化酶活性。使用N - 乙基马来酰亚胺（NEM）和醋酸铅作为巯基抑制剂。用60钴源进行γ射线照射。NEM对腺苷酸环化酶的抑制呈剂量依赖性，在40 - 50微摩尔NEM时观察到50%的抑制率。在较低浓度的醋酸铅（10纳摩尔 - 100微摩尔）下腺苷酸环化酶活性升高，而在较高浓度（高于100微摩尔）下则受到抑制。40微摩尔NEM的存在并未改变腺苷酸环化酶醋酸铅饱和曲线的形状。在100 - 800戈瑞剂量范围内的γ射线照射提高了在5毫摩尔氟化钠存在下测得的腺苷酸环化酶活性，但未改变基础活性。γ射线照射对腺苷酸环化酶的NEM饱和没有显著影响，而对醋酸铅饱和曲线有轻微改变。
