S-adenosyl homocysteine hydrolase (ADOHCYASE, adenosylhomocysteinase, AHCY, SAHH)

Function

• hydrolyzes S-adenosyl-5'-homocysteine to homocysteine & adenosine, a thioether cleavage
• adenosylhomocysteine is a competitive inhibitor of S-adenosylmethionine-dependent methyl transferase reactions, thus AHCY may play a role in control of methylations via regulation of intracellular concentration of adenosylhomocysteine
• amino-acid biosynthesis, homocysteine biosynthesis
• L-homocysteine from S-adenosyl-L-homocysteine: step 1/1
• context: activated methyl cycle

S-adenosyl-L-homocysteine + H2O <--> L-homocysteine + adenosine

Cofactor: binds 1 NAD per subunit

Structure

• homotetramer
• belongs to the adenosylhomocysteinase family

Compartment

• cytoplasm, melanosome

Pathology

• defects in AHCY are a cause of hypermethioninemia

Genetics

Gene locus: 20cen-q13.1

Laboratory

• adenosylhomocysteine hydrolase in erythrocytes

More general terms

• hydrolase

Additional terms

• adenosine (Adenocard, Adenoscan)
• adenosylhomocysteinase 2; AdoHcyase 2; DC-expressed AHCY-like molecule; S-adenosyl-L-homocysteine hydrolase 2; S-adenosylhomocysteine hydrolase-like protein 1 (AHCYL1, DCAL, XPVKONA)
• adenosylhomocysteinase 3; S-adenosyl-L-homocysteine hydrolase 3; AdoHcyase 3 (AHCYL2, KIAA0828)
• homocysteine
• methionine metabolism (trans-sulfuration pathway)
• S-adenosylhomocysteine

Database

• UniProt: http://www.uniprot.org/uniprot/P23526.html
• OMIM: https://mirror.omim.org/entry/180960
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=191