Catalyzes the transfer of a methyl group from methylcob(III)alamin (MeCbl) to homocysteine, yielding enzyme-bound cob(I)alamin and methionine in the cytosol. MeCbl is an active form of cobalamin (vitam...[+]

Catalyzes the transfer of a methyl group from methylcob(III)alamin (MeCbl) to homocysteine, yielding enzyme-bound cob(I)alamin and methionine in the cytosol. MeCbl is an active form of cobalamin (vitamin B12) used as a cofactor for methionine biosynthesis. Cob(I)alamin form is regenerated to MeCbl by a transfer of a methyl group from 5-methyltetrahydrofolate. The processing of cobalamin in the cytosol occurs in a multiprotein complex composed of at least MMACHC, MMADHC, MTRR (methionine synthase reductase) and MTR which may contribute to shuttle safely and efficiently cobalamin towards MTR in order to produce methionine. [-]

             homocystinuria-megaloblastic anemia cblG type
             Down syndrome
             neural tube defect
             methylmalonic aciduria and homocystinuria type cblG
             orofacial cleft

          OROFACIAL CLEFT 1; OFC1
          NEURAL TUBE DEFECTS, FOLATE-SENSITIVE; NTDFS
          DOWN SYNDROME

ClinVar, ClinGen, MalaCards, KEGG Disease, DECIPHER, COSMIC, MARRVEL, GTR, DisGeNET, dbVAR, GHR, gnomAD