The MAT1A gene encodes the enzyme Methionine Adenosyltransferase 1A an enzyme that controls the production of S-adenosylmethionine (SAM) which functions as a methyl donor in the body.
SAM is a methyl donor in the body involved in numerous processes including DNA methylation to regulate gene expression, transsulfuration to convert homocysteine to cysteine and remove sulfur from the body and various other processes. It is formed by MAT1A which uses combines the essential amino acid methionine with a molecule of ATP and water.
MAT1A is sensitive to alterations in other parts of the network; for example, SNPs associated with reduced MTHFR function can lead to reductions in the levels of methionine present which then limits the formation of SAM, inhibiting numerous cellular processes.
The A allele in the MAT1A gene results in a loss of MAT1A function leading to the development of excess of methionine in the blood, which is also associated with a reduction in the amount of SAM available to act as a methyl donor.
The key nutrient cofactors that support this pathway are potassium, magnesium and SAMe. Potassium helps to limit the accumulation of methionine and magnesium helps to limit the accumulation of methionine and providing sufficient SAM.