Methionine adenosyltransferases in liver cancer

Table 1 Mammalian MAT genes and isoenzymes

Gene	Protein	Amino acids	Alternative names	Oligomeric state	Regulatory subunit	Co-factors	Km for methionine	Km for ATP	Ki for SAMe	X-ray structure
MAT1A	MATα1	395	MATIII MAT(α1)2	Dimer	No		210 μmol/L-7 mmol	1-3 mmol	None	20BV
			MATI MAT(α1)4	Tetramer	No		23 μmol/L-1 mmol	0.2-0.5 mmol	400 μmol/L
MAT2A	MATα2	395	MAT(α2)2	Dimer			4-10 μmol/L	70 μmol/L	60 μmol/L	5A19
			MAT(α2)4	Tetramer						5A1I
MAT2B	MATβV1	334		Monomeric		NADP+
	MATβV2	323		Monomeric		NADP+				2YDX

Historically, MATII in the literature refers to complexes of MATα2 and MATβ.