Gaufichon Laure, Rothstein Steven J, Suzuki Akira
INRA, IJPB, UMR1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France.
University of Guelph, Department of Molecular and Cellular Biology, Guelph, Ontario, Canada N1G 2W1.
Plant Cell Physiol. 2016 Apr;57(4):675-89. doi: 10.1093/pcp/pcv184. Epub 2015 Dec 1.
Inorganic nitrogen in the form of ammonium is assimilated into asparagine via multiple steps involving glutamine synthetase (GS), glutamate synthase (GOGAT), aspartate aminotransferase (AspAT) and asparagine synthetase (AS) in Arabidopsis. The asparagine amide group is liberated by the reaction catalyzed by asparaginase (ASPG) and also the amino group of asparagine is released by asparagine aminotransferase (AsnAT) for use in the biosynthesis of amino acids. Asparagine plays a primary role in nitrogen recycling, storage and transport in developing and germinating seeds, as well as in vegetative and senescence organs. A small multigene family encodes isoenzymes of each step of asparagine metabolism in Arabidopsis, except for asparagine aminotransferase encoded by a single gene. The aim of this study is to highlight the structure of the genes and encoded enzyme proteins involved in asparagine metabolic pathways; the regulation and role of different isogenes; and kinetic and physiological properties of encoded enzymes in different tissues and developmental stages.
在拟南芥中，铵态无机氮通过多个步骤被同化为天冬酰胺，这些步骤涉及谷氨酰胺合成酶（GS）、谷氨酸合酶（GOGAT）、天冬氨酸转氨酶（AspAT）和天冬酰胺合成酶（AS）。天冬酰胺的酰胺基团由天冬酰胺酶（ASPG）催化的反应释放，天冬酰胺的氨基也由天冬酰胺转氨酶（AsnAT）释放，用于氨基酸的生物合成。天冬酰胺在发育中和萌发的种子以及营养和衰老器官的氮循环、储存和运输中起主要作用。除了由单个基因编码的天冬酰胺转氨酶外，一个小的多基因家族编码拟南芥中天冬酰胺代谢每个步骤的同工酶。本研究的目的是突出参与天冬酰胺代谢途径的基因和编码酶蛋白的结构；不同同工基因的调控和作用；以及不同组织和发育阶段中编码酶的动力学和生理学特性。
