Zimny-Arndt U, Klose J
J Mol Evol. 1987;24(3):260-71. doi: 10.1007/BF02111239.
Proteins of membranes and cytosols were extracted from the livers and brains of mice (inbred strain DBA/6J) and rats (inbred strain DA/Han) and separated by two-dimensional electrophoresis (2-DE). The 2-DE patterns were compared with regard to qualitative (spot position) and quantitative (spot intensity) characteristics of the proteins of these two species. The following results were obtained: Brain had more (higher percentage) conservative proteins (proteins found in both mice and rats) than liver; plasma membranes had more conservative proteins than the cytosols; organ-unspecific proteins contained more conservative proteins than relatively organ-specific proteins; the pattern of distribution of genetic variability among different classes of proteins represented by findings 1-3 was the same for the qualitative and quantitative characteristics of the proteins; and some observations indicated that quantitative variability occurred more frequently among proteins than did qualitative variability. Our conclusion is that regulatory sequences in the DNA (regulatory genes) are subjected to functional constraints that differ in strength among different classes of proteins by the same ratios as the constraints acting on the structural genes. The overall effect of the selective pressure is, however, less stringent for regulatory genes than for structural genes. The results obtained here by comparing two different species are very similar to previous results we obtained by studying different subspecies (inbred strains of the mouse). From this finding arises a new concept: the study of molecular evolution on the basis of different classes of proteins. Our results were compared with data from the literature that were obtained in part from studies on cultured cells. The comparison suggested that cultured cells have lost their tissue-specific proteins, and so generate predominantly extremely conservative proteins.
从小鼠（近交系DBA/6J）和大鼠（近交系DA/Han）的肝脏和大脑中提取膜蛋白和胞质蛋白，并通过二维电泳（2-DE）进行分离。对这两个物种蛋白质的二维电泳图谱在蛋白质的定性（斑点位置）和定量（斑点强度）特征方面进行了比较。得到以下结果：大脑中的保守蛋白（在小鼠和大鼠中均发现的蛋白）比肝脏中的更多（百分比更高）；质膜中的保守蛋白比胞质溶胶中的更多；器官非特异性蛋白比相对器官特异性蛋白含有更多的保守蛋白；由结果1-3所代表的不同类别蛋白质之间遗传变异性的分布模式在蛋白质的定性和定量特征方面是相同的；并且一些观察结果表明，蛋白质中定量变异性比定性变异性更频繁地发生。我们的结论是，DNA中的调控序列（调控基因）受到功能限制，不同类别的蛋白质之间这种限制的强度按与作用于结构基因的限制相同的比例有所不同。然而，选择性压力对调控基因的总体影响比对结构基因的影响宽松。通过比较两个不同物种在这里获得的结果与我们之前通过研究不同亚种（小鼠近交系）获得的结果非常相似。基于这一发现产生了一个新的概念：基于不同类别蛋白质的分子进化研究。我们的结果与文献数据进行了比较，这些数据部分来自对培养细胞的研究。比较表明，培养细胞已经失去了它们的组织特异性蛋白质，因此主要产生极其保守的蛋白质。
