MAT2a

The enzyme S-adenosylmethionine synthetase, or MAT, catalyzes the formation of S- adenosylmethionine (AdoMet or SAMe) from methionine and ATP. AdoMet is the principal biological source of synthesized methyl, and is found in all cells but most prominently in the liver. In mammalian tissues, there are three distinct AdoMet synthases - the alpha, beta, and gamma isoforms. While the alpha and beta variants are uniquely expressed solely in the adult liver, gamma is more widely distributed in the extrahepatic tissues.

Methionine Adenosyltransferase II alpha, also known as MAT2a, is a catalytic subunit of methionine adenosyltransferase (MAT) and essential enzyme for the catalysis of the principle biological methyl donor, S-adenosylmethionine (SAM) from methionine and ATP. MAT2a's heterotetramer structure is composed of 2 catalytic alpha subunits (alpha and alpha’)¹. During development in the adult human liver, MAT2a and its gene products are progressively replaced by MAT1a during fetal liver development².