The Department Of Genetics, Carnegie Institution of Washington, Cold Spring Harbor, Long Island.
J Gen Physiol. 1962 Mar 1;45(4):77-92. doi: 10.1085/jgp.45.4.77.
A procedure is described for the purification of salmon testis deoxyribonuclease II by means of acid extraction, fractional precipitation with ammonium sulfate, heat denaturation of extraneous proteins, and ethanol fractionation. This process separates the deoxyribonuclease activity from that of ribonuclease, phosphatase, phosphodiesterase, and protease. Over 50 per cent of the activity is retained with an over-all enrichment of 20,000-fold. The enzyme degrades both native and heat-denatured DNA, but the rate of degradation of the latter is only one-tenth that of the former. It does not hydrolyze apurinic acid. The enzyme is most stable in the pH range 4 to 5. Electrolytes are essential for the expression of its activity: monovalent ions satisfy the requirement, but divalent ones are much more effective. Above a certain optimum concentration, each electrolyte is inhibitory. The pH of maximal activity, under conditions of optimal ionic strength, is 4.8; the temperature optimum is near to 55 degrees C.
描述了一种通过酸提取、分步硫酸铵沉淀、热变性外来蛋白和乙醇分级分离来纯化鲑鱼睾丸脱氧核糖核酸酶 II 的方法。该过程将脱氧核糖核酸酶活性与核糖核酸酶、磷酸酶、磷酸二酯酶和蛋白酶活性分离。超过 50%的活性得以保留，总体富集倍数达到 20,000 倍。该酶既能降解天然 DNA，也能降解热变性 DNA，但后者的降解速度仅为前者的十分之一。它不能水解无嘌呤酸。该酶在 pH 值为 4 到 5 的范围内最稳定。电解质对其活性的表达至关重要：单价离子满足要求，但二价离子更为有效。在一定的最佳浓度以上，每种电解质都具有抑制作用。在最佳离子强度条件下，最大活性的 pH 值为 4.8；最适温度接近 55 摄氏度。
