Oldfield S, Jones B L, Tanton D, Proud C G
Department of Biochemistry, School of Medical Sciences, University of Bristol, England.
Eur J Biochem. 1994 Apr 1;221(1):399-410. doi: 10.1111/j.1432-1033.1994.tb18752.x.
The eukaryotic protein synthesis initiation factor, eIF-2B, is a multimeric protein of five different subunits termed alpha, beta, gamma, delta and epsilon, which facilitates recycling of a further factor, eIF-2, and is an important control point in the initiation process. In order to investigate the structure and function of eIF-2B, monoclonal antibodies have been prepared to the beta, delta and epsilon subunits of the factor from rabbit reticulocytes. All three antibodies are active in Western blotting, ELISA and immunoprecipitation. The anti-epsilon antibody inhibits both the guanine nucleotide exchange activity of eIF-2B and protein synthesis in the rabbit reticulocyte lysate at the level of initiation. The other two antibodies do not inhibit either guanine nucleotide exchange or protein synthesis. The monoclonal antibodies and a polyclonal anti-(rabbit reticulocyte eIF-2B) serum were used to investigate the subunit size and the antigenic structure of eIF-2B from a variety of rabbit tissues and from a variety of mammalian species. eIF-2B from all rabbit tissues tested was indistinguishable from that prepared from rabbit reticulocytes. Quantitative studies showed substantial variation in the relative concentrations of eIF-2 and eIF-2B between different rabbit tissues. Marked variation in both the sizes of the subunits and their reaction with the antibodies was observed between eIF-2B from rabbit, rat, guinea pig and man.
真核生物蛋白质合成起始因子eIF-2B是一种由α、β、γ、δ和ε五个不同亚基组成的多聚体蛋白，它促进另一种因子eIF-2的循环利用，是起始过程中的一个重要控制点。为了研究eIF-2B的结构和功能，已制备了针对兔网织红细胞中该因子β、δ和ε亚基的单克隆抗体。这三种抗体在蛋白质免疫印迹法、酶联免疫吸附测定和免疫沉淀中均有活性。抗ε抗体在起始水平抑制eIF-2B的鸟嘌呤核苷酸交换活性以及兔网织红细胞裂解物中的蛋白质合成。另外两种抗体既不抑制鸟嘌呤核苷酸交换也不抑制蛋白质合成。这些单克隆抗体和一种多克隆抗（兔网织红细胞eIF-2B）血清被用于研究来自多种兔组织和多种哺乳动物物种的eIF-2B的亚基大小和抗原结构。所有测试的兔组织中的eIF-2B与从兔网织红细胞制备的eIF-2B没有区别。定量研究表明，不同兔组织之间eIF-2和eIF-2B的相对浓度存在很大差异。在兔、大鼠、豚鼠和人的eIF-2B之间，观察到亚基大小及其与抗体反应的显著差异。
