Nagae S, Ikeda M, Anai M
Biochem Biophys Res Commun. 1983 Nov 15;116(3):952-8. doi: 10.1016/s0006-291x(83)80234-4.
Most of the activity of endodeoxyribonuclease was extracted from isolated chromatin with buffer containing 0.6 M NaCl, indicating that the endonuclease is present as a chromatin-bound form. When nuclei or chromatin of calf thymus or rat liver was digested with the bovine nuclear enzyme in the presence of 2 mM EGTA, to suppress endogenous Ca, Mg-dependent DNase activity, discrete DNA bands with integral multiples of 200 base pairs in length were produced, but no acid-soluble nucleotide was detected. The enzyme made single-strand breaks in pBR322 DNA and degraded it to fragments of limited size. The size of the final products of DNA's of Micrococcus luteus, rat liver nuclei, and calf thymus nuclei was about 3,000, 200, and 160 base pairs, respectively, but the enzyme showed no base specificity. Thus the endonuclease seems preferentially to recognize AT-rich regions of double-stranded DNA and to make single-strand breaks.
大部分脱氧核糖核酸内切酶活性是用含0.6M氯化钠的缓冲液从分离的染色质中提取出来的，这表明该核酸内切酶以染色质结合形式存在。当在2mM乙二醇双乙醚二胺四乙酸（EGTA）存在的情况下，用牛源核酶消化小牛胸腺或大鼠肝脏的细胞核或染色质，以抑制内源性钙、镁依赖性脱氧核糖核酸酶（DNase）活性时，会产生长度为200个碱基对整数倍的离散DNA条带，但未检测到酸溶性核苷酸。该酶在pBR322 DNA中产生单链断裂并将其降解为有限大小的片段。藤黄微球菌、大鼠肝脏细胞核和小牛胸腺细胞核的DNA最终产物大小分别约为3000、200和160个碱基对，但该酶没有碱基特异性。因此，该核酸内切酶似乎优先识别双链DNA中富含AT的区域并产生单链断裂。
