Yamaguchi T, Nishimura S, Takahashi K, Yoshikuni M, Masaki J, Hirai T, Saneyoshi M
Department of Biological Sciences, The Nishi-Tokyo University, Uenohara, Yamanashi.
J Biochem. 1996 Jan;119(1):186-92. doi: 10.1093/oxfordjournals.jbchem.a021207.
DNA polymerase betas from cherry salmon, Oncorhynchus masou, liver and testes were purified to near homogeneity, and no substantial differences between the enzymes were observed. The molecular weight of both enzymes, determined by SDS-polyacrylamide gel electrophoresis, was 39,000. The amino acid sequences of the N-terminus of the liver and testes enzymes were determined and compared with that of the rat enzyme. Of the N-terminal 30 amino acid residues of salmon liver DNA polymerase beta, 21 (70%) were identical to those of the rat enzyme sequence. However, unlike most eukaryotic DNA polymerase betas, the isoelectric points (pIs) of the DNA polymerase betas from salmon liver and testes were both estimated to be 6.2, which is significantly different from the alkaline isoelectric points (pI = 8.5-9.5) established for other highly purified vertebrate DNA polymerase betas. The cherry salmon DNA polymerase betas were still active at below 10 degrees C, compared with the rat enzyme.
从樱花鲑（Oncorhynchus masou）的肝脏和睾丸中纯化出的DNA聚合酶β达到了近乎均一的状态，且未观察到这两种酶之间存在显著差异。通过SDS-聚丙烯酰胺凝胶电泳测定，这两种酶的分子量均为39,000。测定了肝脏和睾丸中酶的N端氨基酸序列，并与大鼠酶的序列进行了比较。在鲑鱼肝脏DNA聚合酶β的N端30个氨基酸残基中，有21个（70%）与大鼠酶序列相同。然而，与大多数真核生物DNA聚合酶β不同的是，鲑鱼肝脏和睾丸中的DNA聚合酶β的等电点（pI）均估计为6.2，这与为其他高度纯化的脊椎动物DNA聚合酶β确定的碱性等电点（pI = 8.5 - 9.5）有显著差异。与大鼠酶相比，樱花鲑DNA聚合酶β在10摄氏度以下仍具有活性。
