Watterson D M, Iverson D B, Van Eldik L J
Biochemistry. 1980 Dec 9;19(25):5762-8. doi: 10.1021/bi00566a015.
Calmodulin is the name proposed for a multifunctional, calcium binding protein whose presence has been detected in a number of eukaryotic cells. In the studies summarized here, calmodulin has been isolated from spinach leaves (Spinacea oleracea), characterized, and compared to vertebrate calmodulins. Quantitative recovery data for a rapid-isolation protocol demonstrate that calmodulin is a major constituent of spinach leaves. Spinach calmodulin is indistinguishable from vertebrate calmodulins in phosphodiesterase activator activity using vertebrate brain phosphodiesterase and in quantitative immunoreactivity using antiserum made against vertebrate calmodulin. However, spinach calmodulin is really distinguished from vertebrate and invertebrate calmodulins in electrophoretic mobility and in amino acid composition. Spinach calmodulin, like vertebrate calmodulins, lacks tryptophan and contains 1 mol each of N epsilon-trimethyllysine and histidine per 17000 g of protein. In contrast to vertebrate calmodulins, spinach calmodulin has only one tyrosinyl residue and has a threonine/serine ratio of 1.3. While amino acid compositions indicate differences between spinach and vertebrate calmodulins, isolation and characterization of tryptic peptides containing the single histidinyl and N epsilon-trimethyllysyl residues and both prolinyl residues indicate that these regions in spinach calmodulin are similar to the corresponding regions in vertebrate calmodulin. These studies more fully define the general and specific characteristics of calmodulins and indicate that calmodulin structure is not as highly conserved among all eukaryotes as it is among vertebrates and invertebrates.
钙调蛋白是一种多功能钙结合蛋白的名称，在许多真核细胞中都已检测到它的存在。在本文总结的研究中，从菠菜叶（菠菜）中分离出了钙调蛋白，对其进行了表征，并与脊椎动物的钙调蛋白进行了比较。一种快速分离方案的定量回收数据表明，钙调蛋白是菠菜叶的主要成分。使用脊椎动物脑磷酸二酯酶时，菠菜钙调蛋白在磷酸二酯酶激活活性方面与脊椎动物钙调蛋白没有区别；使用针对脊椎动物钙调蛋白制备的抗血清时，在定量免疫反应性方面也没有区别。然而，菠菜钙调蛋白在电泳迁移率和氨基酸组成方面确实与脊椎动物和无脊椎动物的钙调蛋白不同。菠菜钙调蛋白与脊椎动物钙调蛋白一样，缺乏色氨酸，每17000克蛋白质含有1摩尔的N-ε-三甲基赖氨酸和组氨酸。与脊椎动物钙调蛋白不同的是，菠菜钙调蛋白只有一个酪氨酸残基，苏氨酸/丝氨酸的比例为1.3。虽然氨基酸组成表明菠菜和脊椎动物钙调蛋白之间存在差异，但对含有单个组氨酸残基、N-ε-三甲基赖氨酸残基和两个脯氨酸残基的胰蛋白酶肽段的分离和表征表明，菠菜钙调蛋白中的这些区域与脊椎动物钙调蛋白中的相应区域相似。这些研究更全面地定义了钙调蛋白的一般和特定特征，并表明钙调蛋白的结构在所有真核生物中不像在脊椎动物和无脊椎动物中那样高度保守。
