Hongo S, Matsumoto T, Sato T
Biochim Biophys Acta. 1978 Jan 12;522(1):258-66. doi: 10.1016/0005-2744(78)90342-x.
Asparagine synthetase (L-aspartate:ammonia ligase (AMP-forming, EC 6.3.1.1) activity in rat liver increased when the animals were put on a low casein diet. The enzyme was purified about 280-fold from the supernatant of rat liver homogenate by a procedure comprising ammonium sulfate fractionation. DEAE-Sepharose column chromatography, and Sephadex G-100 gel filtration. The optimal pH of the enzyme was in the range 7.4-7.6 with glutamine as an amide donor. The molecular weight was estimated to be approximately 110,000 by gel filtration. Chloride ion was required for the enzyme activity. The apparent Km values for L-aspartate, L-glutamine, ammonium chloride, ATP, and Cl- were calculated to be 0.76, 4.3, 10, 0.14, and 1.7 mM, respectively. The activity was inhibited by L-asparagine, nucleoside triphosphates except ATP, and sulfhydryl reagents. It has been observed that the properties of asparagine synthetase from rat liver are not so different from those of tumors such as Novikoff hepatoma and RADA 1.
当给大鼠喂食低酪蛋白饮食时，其肝脏中天冬酰胺合成酶（L-天冬氨酸：氨连接酶（生成AMP，EC 6.3.1.1））的活性会增加。通过包括硫酸铵分级分离、DEAE-琼脂糖柱色谱和葡聚糖G-100凝胶过滤的步骤，从大鼠肝脏匀浆的上清液中纯化该酶约280倍。以谷氨酰胺作为酰胺供体时，该酶的最适pH在7.4 - 7.6范围内。通过凝胶过滤估计其分子量约为110,000。酶活性需要氯离子。L-天冬氨酸、L-谷氨酰胺、氯化铵、ATP和Cl⁻的表观Km值分别计算为0.76、4.3、10、0.14和1.7 mM。该活性受到L-天冬酰胺、除ATP外的核苷三磷酸和巯基试剂的抑制。据观察，大鼠肝脏中天冬酰胺合成酶的性质与诸如诺维科夫肝癌和RADA 1等肿瘤的性质没有太大差异。
