Summary
In a previous publication it has been shown that the radiation induced physiological inactivation of dibutyryl-cAMP was far more pronounced than the chemical modification (Schachinger et al. 1981). In this paper it will be shown, that irradiation of dib-cAMP in solution resulted in the formation of monobutyryl cAMP and other not yet completely identified hydroxylated derivatives as well as a decomposition of the purine structure. Moreover, irradiated dib-cAMP inhibited the physiological activity of not irradiated dib-cAMP on the smooth muscle. From the data an effectiveK m -value for dib-cAMP of 2.4 × 10−5 M was determined and an effectiveK I -value of 1.3 × 10−6 M was found for the irradiation products, i.e., a tenfold affinity of the latter compared to unirradiated dib-cAMP. The results are discussed with respect to a better understanding of dose-response curves for chemical and physiological inactivation.
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Schachinger, L., Hagen, U., Klöter, H. et al. Inhibitory effect of irradiation products of cyclic adenosine-monophosphate on the relaxing ability of smooth muscle preparations. Radiat Environ Biophys 21, 97–107 (1982). https://doi.org/10.1007/BF01323641
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DOI: https://doi.org/10.1007/BF01323641