Substrate specificity determinants for casein kinase II as deduced from studies with synthetic peptides.
Substrate specificity determinants for casein kinase II as deduced from studies with synthetic peptides.
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DOI：
10.1016/s0021-9258(18)48058-1
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发表时间：
1987-07
期刊：
影响因子：
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通讯作者：
E. Kuenzel;J. Mulligan;J. Sommercorn;E. Krebs
中科院分区：
文献类型：
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作者：
E. Kuenzel;J. Mulligan;J. Sommercorn;E. Krebs
酪蛋白激酶II的特异性已经通过使用许多不同的合成肽作为底物分析磷酸化反应的动力学而被进一步定义。最好的肽底物是其中在可磷酸化的丝氨酸或苏氨酸的两侧存在多个酸性氨基酸的那些。丝氨酸（苏氨酸）的NH 2-末端侧的酸性残基大大提高了动力学常数，但不是绝对必需的。绝对需要丝氨酸（苏氨酸）COOH末端侧的酸性残基。酸性残基的占据特别关键的一个位置是位于磷酸受体位点的COOH末端的3个残基的位置，尽管在除去4或5个残基的位置中存在酸性氨基酸也可以提供将用作激酶底物的适当结构。天冬氨酸是比谷氨酸更好的氨基酸决定簇。磷酸受体位点周围相对较短的氨基酸序列似乎是酪蛋白激酶II特异性的基础。本研究中的肽还用酪蛋白激酶I和来自乳腺的酪蛋白激酶进行了测定，以便这些激酶的特异性可以与酪蛋白激酶II的特异性进行比较。
The specificity of casein kinase II has been further defined by analyzing the kinetics of phosphorylation reactions using a number of different synthetic peptides as substrates. The best peptide substrates are those in which multiple acidic amino acids are present on both sides of the phosphorylatable serine or threonine. Acidic residues on the NH2-terminal side of the serine (threonine) greatly enhance the kinetic constants but are not absolutely required. Acidic residues on the COOH-terminal side of the serine (threonine) are absolutely required. One position for which the occupation of an acidic residue is especially critical is the position located 3 residues to the COOH terminus of the phosphate acceptor site, although the presence of an acidic amino acid in the positions that are 4 or 5 residues removed may also provide an appropriate structure that will serve as a substrate for the kinase. Aspartate serves as a better amino acid determinant than glutamate. A relatively short sequence of amino acids surrounding the phosphate acceptor site appears to serve as the basis for the specificity of casein kinase II. The peptides in this study were also assayed with casein kinase I and the casein kinase from the mammary gland so that the specificities of these kinases could be compared to that of casein kinase II.