DePaoli-Roach A A, Roach P J, Pham K, Kramer G, Hardesty B
J Biol Chem. 1981 Sep 10;256(17):8871-4.
A protein kinase from rabbit reticulocytes, able to phosphorylate the beta subunit of eukaryotic initiation factor 2 (eIF-2), has been demonstrated to phosphorylate also glycogen synthase. A glycogen synthase kinase (PC0.7) from rabbit skeletal muscle has been shown to phosphorylate the beta subunit of eIF-2. Comparison of highly purified preparations of the two protein kinases has indicated several similarities of properties. 1) Both enzymes were associated with two major polypeptide species, alpha (Mr = 43,000) and beta (Mr = 25,000), and exhibited apparent native molecular weights of 176,000-180,000 by gel filtration and 130,000-140,000 by sucrose density gradient sedimentation. 2) Both enzymes phosphorylated glycogen synthase, eIF-2 beta, phosvitin, and casein and were effective in utilizing GTP and ATP as phosphoryl donors. 3) Both enzymes displayed the same chromatographic behavior on phosvitin-Sepharose, phosphocellulose, and DEAE-cellulose. 4) Both enzymes underwent an autophosphorylation of the beta polypeptide when incubated with ATP and Mg2+. On the basis of these and other properties, we propose that the two protein kinases, if not identical, are very similar enzymes.
已证明兔网织红细胞中的一种蛋白激酶能够磷酸化真核起始因子2（eIF-2）的β亚基，它也能磷酸化糖原合酶。兔骨骼肌中的一种糖原合酶激酶（PC0.7）已被证明可磷酸化eIF-2的β亚基。对这两种蛋白激酶的高度纯化制剂进行比较，发现了几个性质上的相似之处。1）两种酶都与两种主要的多肽种类相关，α（Mr = 43,000）和β（Mr = 25,000），通过凝胶过滤显示的表观天然分子量为176,000 - 180,000，通过蔗糖密度梯度沉降显示为130,000 - 140,000。2）两种酶都能磷酸化糖原合酶、eIF-2β、卵黄高磷蛋白和酪蛋白，并且在利用GTP和ATP作为磷酰供体方面很有效。3）两种酶在卵黄高磷蛋白 - 琼脂糖、磷酸纤维素和DEAE - 纤维素上表现出相同的色谱行为。4）当与ATP和Mg2 +一起孵育时，两种酶都会使β多肽发生自身磷酸化。基于这些以及其他性质，我们提出这两种蛋白激酶，如果不是完全相同的话，也是非常相似的酶。
