Dimmey L J, Gordy W
Department of Physics, Duke University, Durham, North Carolina 27706.
Proc Natl Acad Sci U S A. 1980 Jan;77(1):343-6. doi: 10.1073/pnas.77.1.343.
Hyperfine structure due to (17)O has been measured in irradiated zein and edestin after exposure to gaseous oxygen with (17)O concentrated to 24%. The observations prove that the free radicals produced by ionizing irradiation under vacuum at 300 K are converted by the oxygen to protein-peroxide free radicals X-O((1))-O((2)), with the unpaired electron density in a pi-type orbital predominantly on the peroxide group. From the observed couplings, the 2p(pi) spin densities on zein-peroxide are found to be 0.29 and 0.45 for O((1)) and O((2)), respectively; those on edestin-peroxide are 0.26 and 0.48 for O((1)) and O((2)), respectively.
在将含氧量浓缩至24%的气态氧暴露于辐照玉米醇溶蛋白和麦胚球蛋白后,已测量了由(17)O引起的超精细结构。观察结果证明,在300K真空条件下,电离辐射产生的自由基被氧转化为蛋白质过氧化物自由基X - O(1)-O(2),未成对电子密度在π型轨道中主要分布在过氧化物基团上。根据观察到的耦合情况,发现玉米醇溶蛋白过氧化物上O(1)和O(2)的2p(π)自旋密度分别为0.29和0.45;麦胚球蛋白过氧化物上O(1)和O(2)的2p(π)自旋密度分别为0.26和0.48。