Betaine—homocysteine S-methyltransferase

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 (methyl donor) + homocysteine (hydrogen donor) → dimethylglycine (hydrogen receiver) + methionine (methyl receiver)
Diagram of the action of BHMT
betaine-homocysteine S-methyltransferase
Crystal structure of rat liver betaine homocysteine s-methyltransferase.[1]
Identifiers
EC number2.1.1.5
CAS number9029-78-1
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO

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
Identifiers
SymbolBHMT
NCBI gene635
HGNC1047
OMIM602888
RefSeqNM_001713
UniProtQ93088
Other data
EC number2.1.1.5
LocusChr. 5 q13.1-q15
betaine-homocysteine methyltransferase 2
Identifiers
SymbolBHMT2
NCBI gene23743
HGNC1048
OMIM605932
RefSeqNM_017614
UniProtQ9H2M3
Other data
EC number2.1.1.5
LocusChr. 5 q13

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.

gollark: We are of course not done here.
gollark: It also gives me a current listener count and such which is nice.
gollark: mpd has native HTTP output, but icecast provides better compatibility and some sort of manual buffer control (?) which provides greater audio stability in e.g. the music bot.
gollark: This is, I believe, widely considered the standard for audio streaming servers, although it has some annoying parts.
gollark: Now, mpd feeds into a server called "icecast".

See also

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. PMID 17086380.
  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.


This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.