Li N, Wiesman Z, Liu D, Mattoo A K
Plant Molecular Biology Laboratory, Department of Agriculture/Agricultural Research Service, Beltsville Agricultural Research Center (W), MD 20705-2350.
FEBS Lett. 1992 Jul 20;306(2-3):103-7. doi: 10.1016/0014-5793(92)80978-p.
1-Aminocyclopropane-1-carboxylate (ACC) synthase is a key enzyme in the biosynthesis of the plant hormone, ethylene. We have isolated, sequenced and expressed a functional tomato (cv Pik-Red) ACC synthase gene in Escherichia coli. ACC synthase expressed in E. coli was inactivated by incubation with S-adenosylmethionine (SAM), the half-time of which was concentration dependent. Mixing the tomato fruit protein extract with the cell-free extract from transformed E. coli did not affect SAM-dependent inactivation of ACC synthase activity. Thus, single isoforms of the ACC synthase enzyme, which demonstrate the biochemical features expected of the tomato fruit enzyme, can be expressed in E. coli and their structure-function relationships investigated.
1-氨基环丙烷-1-羧酸（ACC）合酶是植物激素乙烯生物合成中的关键酶。我们已在大肠杆菌中分离、测序并表达了一个功能性番茄（品种Pik-Red）ACC合酶基因。在大肠杆菌中表达的ACC合酶与S-腺苷甲硫氨酸（SAM）孵育后会失活，其半衰期呈浓度依赖性。将番茄果实蛋白提取物与来自转化大肠杆菌的无细胞提取物混合，并不影响ACC合酶活性的SAM依赖性失活。因此，ACC合酶的单个同工型，表现出番茄果实酶预期的生化特性，可在大肠杆菌中表达，并对其结构-功能关系进行研究。
