Methionine is an essential amino acid required for protein synthesis and one-carbon metabolism. Its synthesis is catalyzed by the enzyme methionine synthase. Methionine synthase eventually becomes inactive due to the oxidation of its cob(I)alamin cofactor. The protein encoded by this gene regenerates a functional methionine synthase via reductive methylation. It is a member of the ferredoxin-NADP(+) reductase (FNR) family of electron transferases. Mutations in a similar gene in human have been associated with cblE complementation type homocystinuria-megaloblastic anemia and susceptibility to folate-sensitive neural tube defects. Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, May 2015]