Harmonizome 3.0

methylmalonic aciduria (cobalamin deficiency) cblA type

The protein encoded by this gene is involved in the translocation of cobalamin into the mitochondrion, where it is used in the final steps of adenosylcobalamin synthesis. Adenosylcobalamin is a coenzyme required for the activity of methylmalonyl-CoA mutase. Defects in this gene are a cause of methylmalonic aciduria. [provided by RefSeq, Jul 2008]

methylmalonic aciduria (cobalamin deficiency) cblB type

This gene encodes a protein that catalyzes the final step in the conversion of vitamin B(12) into adenosylcobalamin (AdoCbl), a vitamin B12-containing coenzyme for methylmalonyl-CoA mutase. Mutations in the gene are the cause of vitamin B12-dependent methylmalonic aciduria linked to the cblB complementation group. Alternatively spliced transcript variants have been found. [provided by RefSeq, Apr 2011]

probable lysosomal cobalamin transporter

methylmalonic aciduria (cobalamin deficiency) cblC type, with homocystinuria

The exact function of the protein encoded by this gene is not known, however, its C-terminal region shows similarity to TonB, a bacterial protein involved in energy transduction for cobalamin (vitamin B12) uptake. Hence, it is postulated that this protein may have a role in the binding and intracellular trafficking of cobalamin. Mutations in this gene are associated with methylmalonic aciduria and homocystinuria type cblC. [provided by RefSeq, Oct 2009]

methylmalonic aciduria (cobalamin deficiency) cblD type, with homocystinuria

This gene encodes a mitochondrial protein that is involved in an early step of vitamin B12 metabolism. Vitamin B12 (cobalamin) is essential for normal development and survival in humans. Mutations in this gene cause methylmalonic aciduria and homocystinuria type cblD (MMADHC), a disorder of cobalamin metabolism that is characterized by decreased levels of the coenzymes adenosylcobalamin and methylcobalamin. Pseudogenes have been identified on chromosomes 11 and X.[provided by RefSeq, Nov 2008]

cubilin (intrinsic factor-cobalamin receptor)

Cubilin (CUBN) acts as a receptor for intrinsic factor-vitamin B12 complexes. The role of receptor is supported by the presence of 27 CUB domains. Cubulin is located within the epithelium of intestine and kidney. Mutations in CUBN may play a role in autosomal recessive megaloblastic anemia. [provided by RefSeq, Jul 2008]

methylmalonic aciduria (cobalamin deficiency) cblD type, with homocystinuria pseudogene

methylmalonic aciduria (cobalamin deficiency) cblD type, with homocystinuria pseudogene

cubilin (intrinsic factor-cobalamin receptor) pseudogene 2

cubilin (intrinsic factor-cobalamin receptor) pseudogene 3

cubilin (intrinsic factor-cobalamin receptor) pseudogene 1

cobalamin binding intrinsic factor

This gene is a member of the cobalamin transport protein family. It encodes a glycoprotein secreted by parietal cells of the gastric mucosa and is required for adequate absorption of vitamin B12. Vitamin B12 is necessary for erythrocyte maturation and mutations in this gene may lead to congenital pernicious anemia. [provided by RefSeq, Jul 2008]

methionine adenosyltransferase I, alpha

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, Jul 2008]

methionine sulfoxide reductase A

This gene encodes a ubiquitous and highly conserved protein that carries out the enzymatic reduction of methionine sulfoxide to methionine. Human and animal studies have shown the highest levels of expression in kidney and nervous tissue. The protein functions in the repair of oxidatively damaged proteins to restore biological activity. Alternative splicing results in multiple transcript variants. [provided by RefSeq, May 2014]

methionine adenosyltransferase II, alpha

The protein encoded by this gene catalyzes the production of S-adenosylmethionine (AdoMet) from methionine and ATP. AdoMet is the key methyl donor in cellular processes. [provided by RefSeq, Jun 2011]

methionine adenosyltransferase II, beta

The protein encoded by this gene belongs to the methionine adenosyltransferase (MAT) family. MAT catalyzes the biosynthesis of S-adenosylmethionine from methionine and ATP. This protein is the regulatory beta subunit of MAT. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Nov 2012]

radical S-adenosyl methionine domain containing 2

The protein encoded by this gene is an interferon-inducible antiviral protein that belongs to the S-adenosyl-L-methionine (SAM) superfamily of enzymes. The protein plays a role in cellular antiviral response and innate immune signaling. Antiviral effects result from inhibition of viral RNA replication, interference in the secretory pathway, binding to viral proteins and dysregulation of cellular lipid metabolism. The protein has been found to inhibit both DNA and RNA viruses, including influenza virus, human immunodeficiency virus (HIV-1) and Zika virus. [provided by RefSeq, Sep 2020]

radical S-adenosyl methionine domain containing 1

Enables heme binding activity. Predicted to be involved in porphyrin-containing compound biosynthetic process. Located in mitochondrion. [provided by Alliance of Genome Resources, Mar 2025]

transfer RNA methionine (anticodon CAU)

This record serves to anchor the annotations of this class of tRNAs at multiple locations on the human genome. The placements are predicted using tRNAscan-SE (Lowe, T.M. and Eddy, S.R. 1997. Nucleic Acids Res. 25:955-964, PubMed 9023104).

methionine sulfoxide reductase B1 pseudogene 1

methionine sulfoxide reductase B1

The protein encoded by this gene belongs to the methionine-R-sulfoxide reductase B (MsrB) family. Members of this family function as repair enzymes that protect proteins from oxidative stress by catalyzing the reduction of methionine-R-sulfoxides to methionines. This protein is highly expressed in liver and kidney, and is localized to the nucleus and cytosol. It is the only member of the MsrB family that is a selenoprotein, containing a selenocysteine (Sec) residue at its active site. It also has the highest methionine-R-sulfoxide reductase activity compared to other members containing cysteine in place of Sec. Sec is encoded by the UGA codon, which normally signals translation termination. The 3' UTRs of selenoprotein mRNAs contain a conserved stem-loop structure, designated the Sec insertion sequence (SECIS) element, that is necessary for the recognition of UGA as a Sec codon, rather than as a stop signal. A pseudogene of this locus has been identified on chromosome 19. [provided by RefSeq, Aug 2017]

methionine sulfoxide reductase B3

The protein encoded by this gene catalyzes the reduction of methionine sulfoxide to methionine. This enzyme acts as a monomer and requires zinc as a cofactor. Several transcript variants encoding two different isoforms have been found for this gene. One of the isoforms localizes to mitochondria while the other localizes to endoplasmic reticula. [provided by RefSeq, Jul 2010]

methionine adenosyltransferase II, alpha pseudogene

tRNA methionine elongator pseudogene 1

methionine sulfoxide reductase B2

Predicted to enable actin binding activity; peptide-methionine (R)-S-oxide reductase activity; and zinc ion binding activity. Predicted to be involved in actin filament polymerization and protein repair. Located in mitochondrion. [provided by Alliance of Genome Resources, Mar 2025]