中文摘要：

N 离氨酸 acetylation 是在优核质和初核质的最丰富的 translational 以后修正之一。Escherichia coli 的蛋白质 acetylome 用集体 spectrometry (MS ) 被屏蔽了技术，和许多 acetylated 蛋白质被识别了，包括维生素 5 磷酸盐 oxidase (EcPNPOx ) ，但是生物角色在 EcPNPOx 由离氨酸 acetylation 玩了仍然保持未知。在这研究， EcPNPOx 是第一 overexpressed 并且净化，并且二 acetylated 离氨酸残余被随后的液体层析双人脚踏车团 spectrometry 分析识别。指导地点的 mutagenesis 分析证明 acetylated 离氨酸残余在酶的活动和蛋白质的酶的性质起重要作用。EcPNPOx 能是 non-enzymatically 由乙酰磷酸盐的 acetylated 和由在 vitro 的 CobB 的 deacetylated。而且， acetylated 的酶的活动和 deacetylated EcPNPOx 在 vitro 被比较，并且结果证明 acetylation 导致了它的酶的活动的减少，它能被 CobB deacetylation 救。一起拿，我们的数据建议 CobB 在 vitro 调制 EcPNPOx 的酶的活动。

英文摘要：

Nε-lysine acetylation is one of the most abundant post-translational modifications in eukaryote and prokaryote. Protein acetylome of Escherichia coli has been screened using mass spectrometry （MS） technology, and many acetylated proteins have been identified, including the pyridoxine 5＇-phosphate oxidase （EcPNPOx）, but the biological roles played by lysine acetylation in EcPNPOx still remain unknown. In this study, EcPNPOx was firstly overexpressed and purified, and two acetylated lysine residues were identified by the subsequent liquid chromatography-tandem mass spectrometry analysis. Site-directed mutagenesis analysis demonstrated that acetylated lysine residues play important roles in the enzymatic activity and enzymatic properties of the pro- tein. EcPNPOx could be non-enzymatically acetylated by acetyl-phosphate and deacetylated by Cobb in vitro. Furthermore, enzymatic activities of acetylated and deacetylated EcPNPOx were compared in vitro, and results showed that acetylation led to a decrease of its enzymatic activity, which could be rescued by CobB deacetylation. Taken together, our data suggest that Cobb modu- lates the enzymatic activity of EcPNPOx in vitro.