The preparation, properties, and reactions of succinyl coenzyme A synthetase and its phosphorylated form.
The preparation, properties, and reactions of succinyl coenzyme A synthetase and its phosphorylated form.
复制标题
琥珀酰辅酶 A 合成酶及其磷酸化形式的制备、性质和反应。
DOI：
10.1016/s0021-9258(18)99537-2
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发表时间：
1967
期刊：
影响因子：
--
通讯作者：
P. Boyer
中科院分区：
文献类型：
--
作者：
R. Ramaley;W. A. Bridger;R. W. Moyer;P. Boyer
一种从大肠杆菌中提取的琥珀酰辅酶A合成酶制剂，具有以下特征：表观色谱、沉降和电泳均一性;分子量约为141，000;A280（1 mg/ml）= 0.511;比活性高于以前的制剂;并通过几个标准与暴露于Mg++、无机正磷酸盐和琥珀酰辅酶A或暴露于Mg++和ATP后获得的磷酸化蛋白质（E-P）相同。ATP将磷酸化每摩尔酶的1个组氨酸残基，表观-Δ F为2000 cal，但暴露于Pi和琥珀酰辅酶A时，每摩尔酶可获得一个以上的磷酰基。与催化活性相比，不同制剂的E-P形成能力以一种无法解释的方式变化。辅酶A或琥珀酰辅酶A浓度的增加将引起E-P的净转化，辅酶A是P1与E-P交换所必需的，并轻微地刺激E-P与ATP的交换。
A succinyl coenzyme A synthetase preparation fromEscherichia colihas the following characteristics: apparent chromatographic, sedimentation, and electrophoretic homogeneity; molecular weight of about 141,000;A280(1 mg per ml) = 0.511; higher specific activity than previous preparations; and identity by several criteria with a phosphorylated protein (E-P) obtained upon exposure to Mg++, inorganic orthophosphate, and succinyl-CoA or to Mg++and ATP. ATP will phosphorylate up to 1 histidine residue per mole of enzyme, with an apparent -ΔFof 2000 cal, but more than one phosphoryl group per mole is obtained from exposure to Piand succinyl-CoA. Capacity of different preparations forE-Pformation, as compared to catalytic activity, varies in an unexplained manner. Increases in CoA or succinyl-CoA concentration will cause net Piformation fromE-P. CoA is required for an exchange of PiwithE-P, and slightly stimulates exchange betweenE-Pand ATP.