Regulation of mammalian liver methionine adenosyltransferase
Regulation of mammalian liver methionine adenosyltransferase
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DOI：
10.1093/jn/132.8.2377s
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发表时间：
2002-08-01
影响因子：
4.2
通讯作者：
Mato, JM
中科院分区：
文献类型：
--
作者：
Corrales, FJ;Pérez-Mato, I;Mato, JM
S-腺苷甲硫氨酸（SAM）是所有细胞的必需代谢产物。SAM是最重要的生物甲基供体，是合成多胺的前体。甲硫氨酸腺苷转移酶（MAT; EC 2.5.1.6）催化唯一已知的来自甲硫氨酸和ATP的SAM生物合成反应。在哺乳动物组织中，已经鉴定了三种不同形式的MAT（MAT I、MAT III和MAT II），它们是两种不同基因（MAT 1A和MAT 2A）的产物。尽管MAT 2A在所有哺乳动物组织中表达，但MAT 1A的表达主要限于成体肝脏。在哺乳动物中，高达85%的甲基化反应和高达48%的蛋氨酸代谢发生在肝脏中，这表明该器官在调节血液蛋氨酸中的重要作用。最近的证据表明，SAM不仅是蛋氨酸催化剂中的主要生物甲基供体和中间代谢产物，而且它还是调节肝再生和分化等基本肝功能以及该器官对损伤的敏感性的细胞内控制开关。因此，了解调节MAT I/III（特定肝酶）活性的因素对于了解细胞SAM水平是如何控制的至关重要。
S-adenosylmethionine (SAM) is an essential metabolite in all cells. SAM is the most important biological methyl group donor and is a precursor in the synthesis of polyamines. Methionine adenosyltransferase (MAT; EC 2.5.1.6) catalyzes the only known SAM biosynthetic reaction from methionine and ATP. In mammalian tissues, three different forms of MAT (MAT I, MAT III and MAT II) have been identified that are the product of two different genes (MAT1A and MAT2A). Although MAT2A is expressed in all mammalian tissues, the expression of MAT1A is primarily restricted to adult liver. In mammals, up to 85% of all methylation reactions and as much as 48% of methionine metabolism occurs in the liver, which indicates the important role of this organ in the regulation of blood methionine. Recent evidence indicates that not only is SAM the main biological methyl group donor and an intermediate metabolite in methionine catabolism, but it is also an intracellular control switch that regulates essential hepatic functions such as liver regeneration and differentiation as well as the sensitivity of this organ to injury. Therefore, knowledge of factors that regulate the activity of MAT I/III, the specific liver enzyme, is essential to understand how cellular SAM levels are controlled.