Betaine-homocysteine methyltransferase

betaine-homocysteine S-methyltransferase
EC number CAS number IntEnz BRENDA ExPASy KEGG MetaCyc metabolic pathway
PRIAM PDB structures PDBsum
Gene Ontology EGO

In the field of enzymology, a betaine-homocysteine S-methyltransferase also known as betaine-homocysteine methyltransferase (BHMT) is a zinc metallo-enzyme that catalyzes the transfer of a methyl group from betaine to homocysteine to produce dimethylglycine and methionine respectively:[2]

  • betaine + homocysteine → dimethylglycine + methionine

This enzyme belongs to the family of transferases, specifically those transferring one-carbon group methyltransferases. This enzyme participates in the metabolism of glycine, serine, threonine and also methionine.


In humans, there are two isozymes, BHMT[3][4] and BHMT2,[5][6] each encoded by a separate gene.

betaine-homocysteine methyltransferase
Symbol BHMT
Entrez HUGO OMIM RefSeq UniProt EC number Locus q13.1-q15
betaine-homocysteine methyltransferase 2
Symbol BHMT2
Entrez HUGO OMIM RefSeq UniProt EC number Locus q13

Tissue distribution

BHMT is expressed most predominantly in the liver and kidney.[7]

Clinical significance

Anomalies in homocysteine metabolism have been implicated in disorders ranging from vascular disease to neural tube birth defects such as spina bifida.

See also


Further reading

External links

  • Medical Subject Headings (MeSH)