Inositol polyphosphates are ubiquitous molecular signals in metazoans, as are their pyrophosphorylated derivatives that bear a so-called 'high-energy' phosphoanhydride bond. A structural rationale is provided for the ability of Arabidopsis inositol tris/tetrakisphosphate kinase 1 to discriminate between symmetric and enantiomeric substrates in the production of diverse symmetric and asymmetric myo-inositol phosphate and diphospho-myo-inositol phosphate (inositol pyrophosphate) products. Simple tools are applied to chromatographic resolution and detection of known and novel diphosphoinositol phosphates without resort to radiolabeling approaches. It is shown that inositol tris/tetrakisphosphate kinase 1 and inositol pentakisphosphate 2-kinase comprise a reversible metabolic cassette converting Ins(3,4,5,6)P4 into 5-InsP7 and back in a nucleotide-dependent manner. Thus, inositol tris/tetrakisphosphate kinase 1 is a nexus of bioenergetics status and inositol polyphosphate/diphosphoinositol phosphate metabolism. As such, it commands a role in plants that evolution has assigned to a different class of enzyme in mammalian cells. The findings and the methods described will enable a full appraisal of the role of diphosphoinositol phosphates in plants and particularly the relative contribution of reversible inositol phosphate hydroxykinase and inositol phosphate phosphokinase activities to plant physiology.

中文翻译：

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由肌醇三/四磷酸激酶1（ITPK1）和肌醇五磷酸2-激酶（IPK1）组成的ATP响应代谢盒可缓冲磷酸二磷酸肌醇的水平。

肌醇多磷酸酯是后生动物中普遍存在的分子信号，它们的焦磷酸化衍生物带有所谓的“高能”磷酸酐键。提供了结构原理，用于拟南芥肌醇三/四磷酸激酶1在生产各种对称和不对称的肌醇磷酸酯和二磷酸-肌醇磷酸酯（肌醇焦磷酸酯）产品时区分对称和对映体底物的能力。简单的工具可用于色谱分离和检测已知和新颖的二磷酸肌醇磷酸酯，而无需借助放射性标记方法。结果表明，肌醇三/四磷酸激酶1和肌醇五磷酸2-激酶组成了可逆代谢盒，可转换Ins（3,4,5，6）将P4转化为5-InsP7并以核苷酸依赖性方式返回。因此，肌醇三/四磷酸激酶1是生物能状态与肌醇多磷酸/二磷酸肌醇磷酸代谢之间的联系。因此，它在进化中已赋予哺乳动物细胞中不同类别酶的植物中起着重要作用。所述发现和方法将能够全面评估磷酸二肌醇磷酸酯在植物中的作用，尤其是可逆性肌醇磷酸羟激酶和肌醇磷酸磷酸激酶活性对植物生理的相对贡献。它在进化中赋予哺乳动物细胞中不同类别酶的植物中起着重要作用。所述发现和方法将能够全面评估磷酸二肌醇磷酸酯在植物中的作用，尤其是可逆性肌醇磷酸羟激酶和肌醇磷酸磷酸激酶活性对植物生理的相对贡献。它在进化中赋予哺乳动物细胞中不同种类酶的植物中起着重要作用。所述发现和方法将能够全面评估磷酸二肌醇磷酸酯在植物中的作用，尤其是可逆性肌醇磷酸羟激酶和肌醇磷酸磷酸激酶活性对植物生理的相对贡献。