Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E5, Canada.
Evol Bioinform Online. 2007 Dec 11;3:333-40.
Phosphoenolpyruvate carboxykinase (PCK) is the key enzyme to initiate the gluconeogenic pathway in vertebrates, yeast, plants and most bacteria. Nucleotide specificity divided all PCKs into two groups. All the eukaryotic mammalian and most archaeal PCKs are GTP-specific. Bacterial and fungal PCKs can be ATP-or GTP-specific but all plant PCKs are ATP-specific. Amino acid sequence alignment of PCK enzymes shows that the nucleotide binding sites are somewhat conserved within each class with few exceptions that do not have any clear ATP- or GTP-specific binding motif. Although the active site residues are mostly conserved in all PCKs, not much significant sequence homology persists between ATP- and GTP-dependent PCK enzymes. There is only one planctomycetes PCK enzyme (from Cadidatus Kuenenia stuttgartiensis) that shows sequence homology with both ATP-and GTP-dependent PCKs. Phylogenetic studies have been performed to understand the evolutionary relationship of various PCKs from different sources. Based on this study a flowchart of the evolution of PCK has been proposed.
磷酸烯醇式丙酮酸羧激酶（PCK）是脊椎动物、酵母、植物和大多数细菌中启动糖异生途径的关键酶。核苷酸特异性将所有 PCK 分为两组。所有真核哺乳动物和大多数古菌的 PCK 都是 GTP 特异性的。细菌和真菌的 PCK 可以是 ATP 或 GTP 特异性的，但所有植物的 PCK 都是 ATP 特异性的。PCK 酶的氨基酸序列比对表明，核苷酸结合位点在每个类别内具有一定的保守性，只有少数没有明确的 ATP 或 GTP 特异性结合基序的例外。尽管所有 PCK 中的活性位点残基大多保守，但 ATP 和 GTP 依赖性 PCK 之间几乎没有保持显著的序列同源性。只有一种浮霉菌 PCK 酶（来自 Cadidatus Kuenenia stuttgartiensis）与 ATP 和 GTP 依赖性 PCK 都显示出序列同源性。已经进行了系统发育研究，以了解来自不同来源的各种 PCK 的进化关系。基于这项研究，提出了 PCK 进化的流程图。
