Kramer G, Cimadevilla J M, Hardesty B
Proc Natl Acad Sci U S A. 1976 Sep;73(9):3078-82. doi: 10.1073/pnas.73.9.3078.
Highly purified preparations of hemin-controlled repressor of rabbit reticulocyte contain a 3':5'-cyclic AMP-indenpendent protein kinase activity that phosphorylates the low-molecular-weight (about 38,000) polypeptide chain of the initiation factor that forms a ternary complex with GTP and Met-tRNAf. These preparations also phosphorylate several polypeptide components of reticulocyte 40S ribosomal subunits. However, no significant levels of phosphorylation are observed when casein, histones, Artemia salina 40S ribosomal subunits, or other initiation factor fractions are used as substrates although high levels of phosphorylation are obtained with cruder preparations of the repressor. An antibody to these highly purified preparations of repressor has been obtained from the serum of immunized goats. Preincubation with immune goat IgG results in the neutralization of the inhibitory activity of the repressor, while normal IgG has no effect. Preincubation with immune IgG also abolishes the protein kinase activity responsible for the phosphorylation of the initiation factor and reticulocyte 40S subunits. Histone phosphorylation by crude repressor preparations, on the other hand, is unaffected by preincubation with immune IgG.
高度纯化的兔网织红细胞血红素控制阻遏物制剂含有一种不依赖3':5'-环磷酸腺苷的蛋白激酶活性，该活性可使与鸟苷三磷酸（GTP）和甲硫氨酰-起始转运核糖核酸（Met-tRNAf）形成三元复合物的起始因子的低分子量（约38,000）多肽链发生磷酸化。这些制剂还可使网织红细胞40S核糖体亚基的几种多肽成分发生磷酸化。然而，当以酪蛋白、组蛋白、卤虫40S核糖体亚基或其他起始因子组分作为底物时，未观察到明显的磷酸化水平，尽管使用较粗制的阻遏物制剂可获得高水平的磷酸化。已从免疫山羊的血清中获得针对这些高度纯化的阻遏物制剂的抗体。与免疫山羊免疫球蛋白G（IgG）预孵育会导致阻遏物抑制活性的中和，而正常IgG则无此作用。与免疫IgG预孵育还会消除负责起始因子和网织红细胞40S亚基磷酸化的蛋白激酶活性。另一方面，粗制阻遏物制剂对组蛋白的磷酸化不受与免疫IgG预孵育的影响。
