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.
