Betaine—homocysteine S-methyltransferase

betaine-homocysteine S-methyltransferase
Crystal structure of rat liver betaine homocysteine s-methyltransferase. [1]
Identifiers
EC no.	2.1.1.5
CAS no.	9029-78-1
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Gene Ontology	AmiGO / QuickGO
Search PMC articles PubMed articles NCBI proteins

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 trimethylglycine and a hydrogen ion from homocysteine to produce dimethylglycine and methionine respectively: ^[2]

trimethylglycine

+

 

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.

Isozymes

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

betaine-homocysteine methyltransferase Betaine--homocysteine S-methyltransferase 1 homotetramer, Human Identifiers Symbol BHMT NCBI gene 635 HGNC 1047 OMIM 602888 RefSeq NM_001713 UniProt Q93088 Other data EC number 2.1.1.5 Locus Chr. 5 q13.1-q15 Search for Structures Swiss-model Domains InterPro

betaine-homocysteine methyltransferase 2 Identifiers Symbol BHMT2 NCBI gene 23743 HGNC 1048 OMIM 605932 RefSeq NM_017614 UniProt Q9H2M3 Other data EC number 2.1.1.5 Locus Chr. 5 q13 Search for Structures Swiss-model Domains InterPro

Tissue distribution

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

Clinical significance

Mutations in the BHMT gene are known to exist in humans. Anomalies may influence the metabolism of homocysteine, which is implicated in disorders ranging from vascular disease, autism, and schizophrenia to neural tube birth defects such as spina bifida.

See also

• Betaine

References

1. PDB: 1UMY ​; González B, Pajares MA, Martínez-Ripoll M, Blundell TL, Sanz-Aparicio J (May 2004). "Crystal structure of rat liver betaine homocysteine s-methyltransferase reveals new oligomerization features and conformational changes upon substrate binding". J. Mol. Biol. 338 (4): 771–82. CiteSeerX   10.1.1.320.5080 . doi:10.1016/j.jmb.2004.03.005. PMID   15099744.
2. Pajares MA, Pérez-Sala D (December 2006). "Betaine homocysteine S-methyltransferase: just a regulator of homocysteine metabolism?". Cell. Mol. Life Sci. 63 (23): 2792–803. doi:10.1007/s00018-006-6249-6. hdl: 10261/13799 . PMC   11136095 . PMID   17086380. S2CID   6076708.
3. Garrow TA (September 1996). "Purification, kinetic properties, and cDNA cloning of mammalian betaine-homocysteine methyltransferase". J. Biol. Chem. 271 (37): 22831–8. doi: 10.1074/jbc.271.37.22831 . PMID   8798461.
4. Sunden SL, Renduchintala MS, Park EI, Miklasz SD, Garrow TA (September 1997). "Betaine-homocysteine methyltransferase expression in porcine and human tissues and chromosomal localization of the human gene". Arch. Biochem. Biophys. 345 (1): 171–4. doi:10.1006/abbi.1997.0246. PMID   9281325.
5. Chadwick LH, McCandless SE, Silverman GL, Schwartz S, Westaway D, Nadeau JH (November 2000). "Betaine-homocysteine methyltransferase-2: cDNA cloning, gene sequence, physical mapping, and expression of the human and mouse genes". Genomics. 70 (1): 66–73. doi:10.1006/geno.2000.6319. PMID   11087663.
6. Szegedi SS, Castro CC, Koutmos M, Garrow TA (April 2008). "Betaine-homocysteine S-methyltransferase-2 is an S-methylmethionine-homocysteine methyltransferase". J. Biol. Chem. 283 (14): 8939–45. doi: 10.1074/jbc.M710449200 . PMC   2276374 . PMID   18230605.
7. Sunden SL, Renduchintala MS, Park EI, Miklasz SD, Garrow TA (September 1997). "Betaine-homocysteine methyltransferase expression in porcine and human tissues and chromosomal localization of the human gene". Arch. Biochem. Biophys. 345 (1): 171–4. doi:10.1006/abbi.1997.0246. PMID   9281325.

Further reading

• Klee WA, Richards HH, Cantoni GL (1961). "The synthesis of methionine by enzymic transmethylation. VII Existence of two separate homocysteine methylpherases on mammalian liver". Biochim. Biophys. Acta. 54: 157–64. doi:10.1016/0006-3002(61)90948-9. PMID   14456704.

External links

• Betaine+Homocysteine+Methyltransferase at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
• EC 2.1.1.5