title: Regulation of mammalian liver methionine adenosyltransferase.
abstract: 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.
authors.affiliation: Division of Hepatology and Gene Therapy, School of Medicine, University of Navarra, 31008 Pamplona, Spain.
authors.forename: Fernando J
authors.initials: FJ
authors.lastname: Corrales
authors.forename: Isabel
authors.initials: I
authors.lastname: Pérez-Mato
authors.forename: Manuel M
authors.initials: MM
authors.lastname: Sánchez Del Pino
authors.forename: Félix
authors.initials: F
authors.lastname: Ruiz
authors.forename: Carmen
authors.initials: C
authors.lastname: Castro
authors.forename: Elena Ruiz
authors.initials: ER
authors.lastname: García-Trevijano
authors.forename: Uxue
authors.initials: U
authors.lastname: Latasa
authors.forename: M Luz
authors.initials: ML
authors.lastname: Martínez-Chantar
authors.forename: Alfonso
authors.initials: A
authors.lastname: Martínez-Cruz
authors.forename: Matías A
authors.initials: MA
authors.lastname: Avila
authors.forename: José M
authors.initials: JM
authors.lastname: Mato
mesh_terms: D000818:Animals; D005609:Free Radicals; D015971:Gene Expression Regulation, Enzymologic; D008099:Liver / Q000201:enzymology*; D008715:Methionine / Q000378:metabolism; D008716:Methionine Adenosyltransferase / Q000235:genetics*
chemical_list: D005609:Free Radicals; D008715:Methionine; D008716:Methionine Adenosyltransferase