Waldstein E A, Peller S, Setlow R B
Proc Natl Acad Sci U S A. 1979 Aug;76(8):3746-50. doi: 10.1073/pnas.76.8.3746.
We describe the partial purification of an endonuclease from calf thymus that nicks phage PM2 DNA irradiated with UV doses producing only a few pyrimidine dimers per molecule. It has much less activity on DNA that has been subjected to enzymatic photoreactivation after UV irradiation. The calf thymus endonuclease is different from other mammalian UV-endonucleases so far described in that it seems to be dimer specific. The enzyme is stimulated by Mg2+ and is inactive in the presence of EDTA. It binds to UV-irradiated DNA-Sepharose from which it is released by low concentrations of KCl. Gel filtration data indicate that the endonuclease may belong to a high molecular weight protein or protein complex. The enzyme is very labile and freezing increases its lability.
我们描述了从小牛胸腺中部分纯化一种核酸内切酶的过程，该酶能切割经紫外线照射的噬菌体PM2 DNA，这种照射剂量使得每个分子仅产生少数嘧啶二聚体。它对紫外线照射后经酶促光复活处理的DNA活性要低得多。小牛胸腺核酸内切酶与迄今所描述的其他哺乳动物紫外线核酸内切酶不同，因为它似乎对二聚体具有特异性。该酶受Mg2+刺激，在EDTA存在下无活性。它能与紫外线照射过的DNA-琼脂糖结合，低浓度的KCl可将其从结合物中释放出来。凝胶过滤数据表明，该核酸内切酶可能属于一种高分子量蛋白质或蛋白质复合物。这种酶非常不稳定，冷冻会增加其不稳定性。
