Chung H K, Rhee S G
Proc Natl Acad Sci U S A. 1984 Aug;81(15):4677-81. doi: 10.1073/pnas.81.15.4677.
Glutamine synthetase [GS; L-glutamate:ammonia ligase (ADP-forming), EC 6.3.1.2] from Escherichia coli is composed of 12 identical subunits arranged in two superimposed hexagonal arrays. Therefore, partially adenylylated GS is a mixture of hybrid molecules containing different numbers (from 0 to 12) and distributions of adenylylated subunits. In an effort to separate these GS species into uniquely adenylylated molecular species, immunoadsorbants were prepared by covalent attachment of monoclonal antibodies, 72-76-1 (IgG2a and 37-2-1 (IgM), to Affi-Gel 10. The bound GS was eluted with AMP gradients. The results indicate that the IgG column and IgM column yield significantly different elution profiles; the column prepared with the IgG monoclonal antibody better resolves GS containing fewer than 3 adenylylated subunits per dodecamer, whereas the column prepared from the IgM monoclonal antibody better resolves the GS containing higher numbers (from 4 to 12) of adenylylated subunits. In addition, the results indicate that both the distribution and the number of adenylylated subunits are important factors in this separation.
来自大肠杆菌的谷氨酰胺合成酶[GS；L-谷氨酸：氨连接酶（形成ADP），EC 6.3.1.2]由12个相同的亚基组成，排列成两个叠加的六边形阵列。因此，部分腺苷酸化的GS是含有不同数量（从0到12）和腺苷酸化亚基分布的杂合分子的混合物。为了将这些GS种类分离成独特的腺苷酸化分子种类，通过将单克隆抗体72-76-1（IgG2a）和37-2-1（IgM）共价连接到Affi-Gel 10上制备免疫吸附剂。结合的GS用AMP梯度洗脱。结果表明，IgG柱和IgM柱产生明显不同的洗脱曲线；用IgG单克隆抗体制备的柱能更好地分离每个十二聚体中腺苷酸化亚基少于3个的GS，而用IgM单克隆抗体制备的柱能更好地分离腺苷酸化亚基数量较多（从4到12）的GS。此外，结果表明腺苷酸化亚基的分布和数量都是这种分离中的重要因素。
