蛋氨酸特异性合成途径关键酶——高丝氨酸O-酰基转移酶的研究进展

在蛋氨酸生物合成过程中，蛋氨酸特异性合成反应的第一步是高丝氨酸酰基化，由高丝氨酸O-酰基转移酶催化，生成酰基高丝氨酸。高丝氨酸O-酰基转移酶受到末端产物蛋氨酸和S-腺苷蛋氨酸的反馈抑制和反馈阻遏，且高温下极易失活，严重影响碳流流向蛋氨酸，是蛋氨酸生物合成的关键酶，因此对高丝氨酸O-酰基转移酶的研究和改造具有重要意义。但目前关于高丝氨酸O-酰基转移酶的改造和研究较少，在微生物代谢途径中，碳流不能过多流入蛋氨酸合成途径，制约了微生物过量积累蛋氨酸，阻碍了发酵法生产蛋氨酸的工业进程。本文简述了高丝氨酸O-酰基转移酶在蛋氨酸生物合成途径中的作用，在介绍该酶的结构、催化机制和研究现状的基础上，提出该酶在反馈抑制和提高稳定性方面的分子改造策略。

Recent Progress in the Study of Homoserine O-Acyltransferase,the Key Enzyme in the Methionine Biosynthesis Pathway

The first step in methionine synthesis is homoserine acylation catalyzed by homoserine acyltransferase to generate acylhomoserine. Homoserine O-acyltransferase, the key enzyme for methionine biosynthesis, is feedback inhibited or feedback repressed by the end products methionine and S-adenosylmethionine, and is easily inactivated at high temperatures, thus seriously affecting the flow of carbon toward methionine. In this context, studying and modifying homoserine O-acyltransferase are of great significance. However, there are few reports in the literature on studies and modification of homoserine O-acyltransferase. In the microbial metabolic pathways, inadequate carbon flow toward the methionine synthesis pathway can restrict microbial accumulation of methionine, and consequently hinder the industrial fermentation of methionine. In this paper, the role of homoserine O-acyltransferase in the methionine biosynthetic pathway is briefly described. Based on the structure catalytic mechanism of the enzyme as well as a review of recent studies on it, molecular modification strategies for feedback inhibition regulation and stability improvement are proposed.