Nadano D, Yasuda T, Kishi K
Department of Legal Medicine, Fukui Medical School, Japan.
Clin Chem. 1993 Mar;39(3):448-52.
In the single radial enzyme-diffusion (SRED) method for assay of deoxyribonuclease I, a precisely measured volume of the enzyme solution is dispensed into a circular well in an agarose gel layer in which DNA and ethidium bromide are uniformly distributed. A circular dark zone is formed as the enzyme diffuses from the well radially into the gel and digests substrate DNA. The diameter of the dark circle of hydrolyzed DNA increases in size with time and correlates linearly with the amount of enzyme applied to the well. Thus, the SRED can be used for quantitation of deoxyribonuclease I with a limit of detection of 2 x 10(-6) unit. This corresponds to 1 pg of purified urine deoxyribonuclease I. We measured the deoxyribonuclease I activity of 17 different human tissues and body fluids from healthy donors. Urine samples showed the greatest activity, 6.0 +/- 2.2 kilo-units/g protein (mean +/- SD). Serum deoxyribonuclease I activity was 4.4 +/- 1.8 units/L.
在用于测定脱氧核糖核酸酶I的单径向酶扩散（SRED）方法中，将精确测量体积的酶溶液加入到琼脂糖凝胶层中的圆形孔中，DNA和溴化乙锭在该凝胶层中均匀分布。当酶从孔中径向扩散到凝胶中并消化底物DNA时，会形成一个圆形暗区。水解DNA的暗圈直径随时间增大，并且与加入孔中的酶量呈线性相关。因此，SRED可用于定量脱氧核糖核酸酶I，检测限为2×10^(-6)单位。这相当于1 pg纯化的尿脱氧核糖核酸酶I。我们测量了来自健康供体的17种不同人体组织和体液中的脱氧核糖核酸酶I活性。尿液样本显示出最高活性，为6.0±2.2千单位/克蛋白质（平均值±标准差）。血清脱氧核糖核酸酶I活性为4.4±1.8单位/升。
