中文摘要：

当环境中存在多种生长介质时，微生物会利用自身的代谢调控系统优先选择最适碳源达到最佳的生长，同时抑制非优势碳源的利用，这种现象n1做碳代谢抑制。目前已知有CbrAB／Crc、CyoABCDE及PTS^Ntr三个系统参与假单胞菌中碳代谢抑制调控。其中CbrAB／Crc系统由双组份CbrA／CbrB、非编码sRNA以及RNA结合蛋白Crc组成，通过自由Crc的水平来调控非优势碳源代谢基因的转录。CyoABCDE系统由一些末端氧化酶构成，通过电子转移来调控非优势碳源代谢基因的表达。PTS^Ntr系统由PtsP、PtsO及PtsN三种蛋白组成，通过系统的磷酸化激活PtsN从而对代谢基因进行调控。本文将详细介绍了假单胞菌中三种碳代谢抑制调控系统的作用机制。

英文摘要：

Bacteria have metabolism regulation systems that allow cells to selectively assimilate a preferred compound among a mixture of several potential carbon sources, at the same time inhibiting the use of non-perferred carbon sources. This process is known as carbon catabolite repression （CCR）. Current studies have revealed three different systems to be involved in catabolite repression： CbrAB/Crc, CyoABCDE and PTS^Ntr. CbrAB/Crc system is composed of two component system CbrA/CbrB, non- coding RNA and Crc protein, which can regulate gene transcription of non-preferred carbon sources through modulating the level of free Crc. CyoABCDE system contains several terminal oxidases, which control non-preferred carbon sources through coordinating the composition of the electron transport chain. PTS^Ntr system is comprised of PtsP protein, PtsO protein and PtsN protein, which act on CCR through the phosphorylation of PtsN protein. In this paper, we summarize the regulation mechanisms of CCR in Pseudomonas.