Catterall J F, Welker N E
J Bacteriol. 1977 Feb;129(2):1110-20. doi: 10.1128/jb.129.2.1110-1120.1977.
A restriction endonuclease was isolated from Bacillus stearothermophilus1503-4R (Bst1503) and purified to homogeneity. The enzyme required Mg2+ ion as a cofactor. Bst1503 exhibited maximal activity between pH 7.5 and 8.0, between 60 and 65 degrees C, and with about 0.2 mM Mg2+. Bst1503 was not inactivated after exposure at 55 or 65 degrees C for up to 10 h. After 2 h of incubation at 70 degrees C, Bst1503 was inactivated by 65%. Bst1503 was rapidly inactivated at 75 degrees C. A single protein-staining band having a molecular weight of 46,000 was observed when Bst1503 was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme was found to exist in two active forms, the predominating form with an S value of 8.3 (180,000) and the second form with an S value of 5.4 (96,000). No conversion between the 8.3S and 5.4S forms was observed after storage. Bst1503 recognized six sites in TP-1C deoxyribonucleic acid (DNA), one site in pSC101 and simian virus 40 DNAs, and three sites in lambdavir DNA. Bst1503 and BamHI were determined to be isoschizomers. The effect of temperatures on the activity and stability of BamHI was determined.
从嗜热脂肪芽孢杆菌1503 - 4R（Bst1503）中分离出一种限制性内切酶，并将其纯化至同质。该酶需要Mg2 +离子作为辅助因子。Bst1503在pH 7.5至8.0之间、60至65摄氏度之间以及约0.2 mM Mg2 +存在的条件下表现出最大活性。Bst1503在55或65摄氏度下暴露长达10小时后不会失活。在70摄氏度下孵育2小时后，Bst1503失活65%。Bst1503在75摄氏度下迅速失活。当通过十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳分析Bst1503时，观察到一条分子量为46,000的单一蛋白质染色带。发现该酶以两种活性形式存在，主要形式的S值为8.3（180,000），第二种形式的S值为5.4（96,000）。储存后未观察到8.3S和5.4S形式之间的转化。Bst1503在TP - 1C脱氧核糖核酸（DNA）中识别六个位点，在pSC101和猿猴病毒40 DNA中识别一个位点，在λ噬菌体DNA中识别三个位点。已确定Bst1503和BamHI是同裂酶。测定了温度对BamHI活性和稳定性的影响。
