The immediate precursor of ethylene in higher plants is 1-aminocyclopropane-1-carboxylic acid (ACC), which is a product of the reaction controlled by 1-aminocyclopropane-1-carboxylate synthase catalytic activity (S-adenosyl-L-methionine methylthioadenosine-lyase, EC 4.4.1.14). This review summarizes the up-to-date knowledge about organization and gene structure, and transcriptional expression of ACS genes from different plant species hitherto characterized. ACS is encoded by a highly divergent multigene family in each plant species. For example, the ACS families of tomato ( LE-ACS ) and Arabidopsis thaliana (AT-ACS) include numerous isoenzyme genes. Expression of selected members of the multigene ACS family in higher plants is induced by a diverse group of external and internal ethylene inducers such as: wounding, anaerobiosis, viral and fungal infection, chilling, drought, heavy metals, auxin, ripening and senescence processes. Enhanced transcription is the main regulatory step of this enzyme activity but the posttranscriptional regulation is operational as well.

中文翻译：

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1-氨基环丙烷-1-羧酸合酶—基因和表达

高等植物中乙烯的直接前体是1-氨基环丙烷-1-羧酸（ACC），它是由1-氨基环丙烷-1-羧酸酯合酶催化活性控制的反应产物（S-腺苷-L-蛋氨酸甲硫基腺苷-裂解酶，EC 4.4.1.14）。这篇综述总结了有关迄今表征的来自不同植物物种的ACS基因的组织和基因结构以及转录表达的最新知识。ACS由每个植物物种中高度分化的多基因家族编码。例如，番茄的ACS家族（ LE-ACS ）和 拟南芥（AT-ACS） 包括许多同工酶基因。多基因ACS家族的选定成员在高等植物中的表达是由多种外部和内部乙烯诱导剂诱导的，例如：伤口，厌氧菌，病毒和真菌感染，寒冷，干旱，重金属，生长素，成熟和衰老过程。增强的转录是该酶活性的主要调节步骤，但是转录后调节也是可操作的。