Stumpo V M, Trumbore C N
Department of Chemistry and Biochemistry, University of Delaware, Newark 19716.
Int J Radiat Biol. 1991 May;59(5):1101-14. doi: 10.1080/09553009114551011.
Ultraviolet difference spectra between gamma-irradiated and unirradiated aqueous solutions of oxygenated adenine reveal spectral maxima at 224, 286 and 360 nm, and suggest the existence of multiple radiation products. The presence of long-wavelength absorbing products implies the extension of the conjugation of the adenine ring. The product absorbing at 360 nm appears only in the presence of oxygen, with its yield dependent on both oxygen concentration and temperature. The absorbance peak at 360 nm in the UV difference spectra appears to demonstrate simple first-order decay kinetics, with a half-life of 50 min at 3 degrees C. At temperatures below 23 degrees C relative yields of the radiation products are approximately constant, suggesting a common mechanism. Higher temperatures apparently induce a mechanistic alteration. Since the temperature during and subsequent to irradiation, as well as the oxygen concentration of the solution, affects the absolute yields and distribution of the radiation products, great care must be exercised in controlling these variables.
γ辐照和未辐照的氧化腺嘌呤水溶液之间的紫外差示光谱在224、286和360纳米处显示出光谱最大值，并表明存在多种辐射产物。长波长吸收产物的存在意味着腺嘌呤环共轭的延伸。在360纳米处有吸收的产物仅在有氧的情况下出现，其产率取决于氧浓度和温度。紫外差示光谱中360纳米处的吸光度峰值似乎呈现简单的一级衰减动力学，在3℃时半衰期为50分钟。在低于23℃的温度下，辐射产物的相对产率大致恒定，这表明存在一种共同的机制。较高的温度显然会引起机制的改变。由于辐照期间及之后的温度以及溶液中的氧浓度会影响辐射产物的绝对产率和分布，因此在控制这些变量时必须格外小心。
