Kuhnlein U, Penhoet E E, Linn S
Proc Natl Acad Sci U S A. 1976 Apr;73(4):1169-73. doi: 10.1073/pnas.73.4.1169.
Endonuclease activity upon depurinated DNA was measured in extracts of cultured fibroblasts from xeroderma pigmentosum patients. Cell lines from complementation groups A, B, C, E, and the XP-variant had slightly reduced levels of activity, but cell lines from complementation group D had one-sixth of the normal activity. An altered pH dependence and a higher apparent Km for substrate in D-cell lines indicate that the remaining activity is also qualitatively different from the activity found in normal cells. A higher Km was also found in cell lines from the A-complementation group but not in cell lines from the C-complementation group. These defects in apurinic DNase might account for the neurological disorders in patients from the D- and the A-complementation groups.
在对来自着色性干皮病患者的培养成纤维细胞提取物中,测定了脱嘌呤DNA上的核酸内切酶活性。来自互补组A、B、C、E以及XP变异型的细胞系活性水平略有降低,但来自互补组D的细胞系活性仅为正常活性的六分之一。D细胞系中pH依赖性的改变以及底物的表观Km值较高,表明剩余活性在性质上也与正常细胞中的活性不同。在A互补组的细胞系中也发现了较高的Km值,但在C互补组的细胞系中未发现。这些无嘌呤脱氧核糖核酸酶的缺陷可能是导致D互补组和A互补组患者出现神经疾病的原因。