原核细胞精氨酸生物合成途径的研究进展

Research Progress of the Arginine Biosynthetic Pathway in Prokaryotic Cells

原核生物的精氨酸生物合成包含8个酶系,起始于乙酰谷氨酸激酶催化的谷氨酸的乙酰化。到第五步乙酰基团脱离,乙酰谷氨酸通过3个酶的作用,进一步合成乙酰化中间产物。鸟氨酸被氨甲酰基化生成瓜氨酸,天冬氨酸介入后形成精氨琥珀酸,最后形成终产物精氨酸。主要就精氨酸生物合成途径、合成过程中主要酶系及反馈抑制蛋白的作用机制进行了概述。此外,提出了目前精氨酸代谢研究中存在的问题及未来的研究方向。

Arginine biosynthesis in prokaryotes consists of eight enzymatic steps, starting with acetylation of glutamate, catalysed by N-acetylglutamate synthase（NAGS）. After metabolisation of N-acetylglutamate, biosynthesis proceeds via three enzymatic steps which form further acetylated intermediates, until the acetyl group is removed in the fifth step of this process. The resulting ornithine is carbamoylated to citrulline. Addition of aspartate leads to N-argininosuccinate, which is finally converted to L-arginine. Here we summarize the arginine biosynthetic pathway, catalytic mechanisms of enzymes and the molecular mechanisms of feedback inhibition of ArgR protein. In addition, we briefly outline existing problems in the research of arginine metabolism and directions for future research.