Tanaka M, Shibata H
Eur J Biochem. 1985 Sep 2;151(2):291-7. doi: 10.1111/j.1432-1033.1985.tb09099.x.
Two poly(L-proline)-binding proteins (PBP-1 and PBP-2) were purified from chick embryos by using a poly(L-proline)-agarose column. PBP-1 was composed of two different polypeptides (molecular masses of 42 kDa and 15 kDa). The molar ratio of the two proteins in the complex was 1:1. The other poly(L-proline)-binding protein, PBP-2, was the 15-kDa protein itself. The 42-kDa protein was confirmed to be an actin from the amino acid composition, by immunochemical evidence and by its ability to self-polymerize. In addition, the 42 + 15-kDa protein complex (PBP-1) inhibited DNase I, just as a monomeric actin did. The amino acid composition of the 15-kDa protein was similar to that of mammalian profilin and it inhibited the salt-induced polymerization of rabbit skeletal muscle actin. Therefore, we conclude that the two poly(L-proline)-binding proteins from the chick embryo are a profilactin and a profilin in chick embryo. The ability of profilactin to bind poly(L-proline) must be due to profilin itself, because the profilin has a greater affinity for poly(L-proline) than does profilactin. Additionally, both the monomeric and filamentous actin from rabbit skeletal muscle have no affinity for poly(L-proline).
通过使用聚（L-脯氨酸）-琼脂糖柱从鸡胚中纯化出两种聚（L-脯氨酸）结合蛋白（PBP-1和PBP-2）。PBP-1由两种不同的多肽组成（分子量分别为42 kDa和15 kDa）。复合物中这两种蛋白的摩尔比为1:1。另一种聚（L-脯氨酸）结合蛋白PBP-2就是15 kDa的蛋白本身。通过氨基酸组成、免疫化学证据及其自身聚合能力证实42 kDa的蛋白是肌动蛋白。此外，42 + 15 kDa的蛋白复合物（PBP-1）抑制DNase I的作用，就如同单体肌动蛋白一样。15 kDa蛋白的氨基酸组成与哺乳动物的肌动蛋白结合蛋白相似，并且它抑制兔骨骼肌肌动蛋白的盐诱导聚合。因此，我们得出结论，鸡胚中的两种聚（L-脯氨酸）结合蛋白分别是鸡胚中的肌动蛋白结合蛋白和肌动蛋白结合蛋白。肌动蛋白结合蛋白结合聚（L-脯氨酸）的能力必定归因于肌动蛋白结合蛋白本身，因为肌动蛋白结合蛋白对聚（L-脯氨酸）的亲和力比肌动蛋白结合蛋白更强。此外，兔骨骼肌的单体和丝状肌动蛋白对聚（L-脯氨酸）均无亲和力。
