Jaenicke L, Berson W
Hoppe Seylers Z Physiol Chem. 1977 Jul;358(7):883-9. doi: 10.1515/bchm2.1977.358.2.883.
Glutamine synthetase was purified to homogeneity from fresh brain homogenates by a procedure that makes use of the affinity of this ATP requiring ligase to Cibacron 3G-A Blue-Sephadex G-75. It is shown that the interaction of pig brain enzyme with the dye does not concern the active centre but a non-catalytic although specific ATP binding site. Both sides contain a cysteine residue which may react with N-ethylmaleimide. The unprotected succinimidated enzyme is inactive, and aggregates. ATP alone protects only against aggregation, not against inactivation; the ATP/Mg2 complex also hinders inactivation. A tryptic heptadecapeptide isolated from the derivatized enzyme representing the carboxy terminal seems to belong to the active centre; its amino acid sequence was partially determined.
谷氨酰胺合成酶通过利用这种依赖ATP的连接酶与汽巴克隆3G-A蓝葡聚糖G-75的亲和力，从新鲜脑匀浆中纯化至同质。结果表明，猪脑酶与染料的相互作用不涉及活性中心，而是一个非催化但特异性的ATP结合位点。两侧均含有一个可与N-乙基马来酰亚胺反应的半胱氨酸残基。未受保护的琥珀酰化酶无活性且会聚集。单独的ATP仅能防止聚集，不能防止失活；ATP/Mg2复合物也能阻止失活。从代表羧基末端的衍生化酶中分离出的胰蛋白酶十七肽似乎属于活性中心；其氨基酸序列已部分确定。
