MAT1A

This gene catalyzes a two-step reaction that involves the transfer of the adenosyl moiety of ATP to methionine to form S-adenosylmethionine and tripolyphosphate, which is subsequently cleaved to PPi and Pi. S-adenosylmethionine is the source of methyl groups for most biological methylations. The encoded protein is found as a homotetramer (MAT I) or a homodimer (MAT III) whereas a third form, MAT II (gamma), is encoded by the MAT2A gene. Mutations in this gene are associated with methionine adenosyltransferase deficiency. [provided by RefSeq]

Full Name

methionine adenosyltransferase I, alpha

Function

Catalyzes the formation of S-adenosylmethionine from methionine and ATP. The reaction comprises two steps that are both catalyzed by the same enzyme: formation of S-adenosylmethionine (AdoMet) and triphosphate, and subsequent hydrolysis of the triphosphate.

Biological Process

Methionine catabolic process Source: UniProtKB
One-carbon metabolic process Source: UniProtKB-KW
Protein homotetramerization Source: UniProtKB
S-adenosylmethionine biosynthetic process Source: ComplexPortal

Cellular Location

Cytosol
Other locations
methionine adenosyltransferase complex

Involvement in disease

Methionine adenosyltransferase deficiency (MATD):
An inborn error of metabolism resulting in isolated hypermethioninemia. Most patients have no clinical abnormalities, although some neurologic symptoms may be present in rare cases with severe loss of methionine adenosyltransferase activity.

PTM

S-nitrosylation of Cys-120 inactivates the enzyme.
An intrachain disulfide bond can be formed. The protein structure shows that the relevant Cys residues are in a position that would permit formation of a disulfide bond.