Methionine adenosyltransferases (MAT's) are central enzymes in living organisms that have
been conserved with a high degree of homology among species. In the liver, MAT I and III …

Cobalamin‐dependent methionine synthase catalyzes the transfer of a methyl group from
N5‐methyltetrahydrofolate to homocysteine, producing tetrahydrofolate and methionine …

Methylmalonic acidaemia and homocystinuria (MMA/HC) is a very rare inborn error of
cellular metabolism of cobalamin (Cbl), that results in functional defects of both …

Severe methylenetetrahydrofolate reductase (MTHFR) deficiency is an inborn error of folate
metabolism, and is inherited as an autosomal recessive trait. MTHFR is a key enzyme in …

Methyltetrahydrofolate, the major form of folate in plasma, is a carbon donor for the
remethylation of homocysteine to methionine. This form of folate is generated from 5, 10 …

Inborn errors of vitamin B12 (cobalamin) metabolism are characterized by decreased
production of active cobalamin cofactors and subsequent deficiencies in the activities of …

The conversion of labeled formate to methionine and serine, as a measure of remethylation
of homocysteine to methionine and folate coenzyme cycling, has been studied in control and …

Cobalamin is an essential cofactor for two mammalian enzymes: methionine synthase and
methylmalonyl‐CoA mutase. Patients with the cobalamin C (CblC) defect have combined …

Cobalamin deficiency leads to impaired folate function as demonstrated by markedly
impaired single-carbon unit transfer into purine, thymidine and methionine. This occurs in …

Four subjects with thermolabile methylenetetrahydrofolate reductase (MTHFR) were
discovered among 16" obligate" heterozygotes for severe MTHFR deficiency and their family …