betaine-homocysteine S-methyltransferase 1 (BHMT)

Function

• role in regulation of homocysteine metabolism
• converts betaine to dimethylglycine & & homocysteine to methionine
• required for irreversible oxidation of choline
• amine & polyamine degradation; betaine degradation sarcosine from betaine: step 1/2
• amino-acid biosynthesis;
• L-methionine biosynthesis via de novo pathway; L-methionine from L-homocysteine (BhmT route): step 1/1

trimethylammonioacetate + L-homocysteine = dimethylglycine + L-methionine

Cofactor: binds 1 Zn+2 per subunit

Structure

• homotetramer
• contains 1 Hcy-binding domain

Compartment

cytoplasm

Expression

found exclusively in liver & kidney

More general terms

• betaine-homocysteine S-methyltransferase

Additional terms

• betaine (trimethylglycine)
• homocysteine

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=635
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:635
• OMIM: https://mirror.omim.org/entry/602888
• UniProt: http://www.uniprot.org/uniprot/Q93088.html