Genome Property Definition Page
| Accession | GenProp0789 |
| Name | homocysteine regeneration from S-adenosylhomocysteine |
| Type | METAPATH |
| Description | S-adenosylmethionine (SAM) is used in cells as a methyl donor by a large guild of methyltransferases, leaving S-adenosylhomocysteine (SAH). SAH can be cleaved in one step to adenosine and homocysteine by adenosylhomocysteinase (EC 3.3.1.1). The homocysteine can then be used to regenerate methionine. Alternatively, it can be cleaved in two steps. First adenine is removed by adenosylhomocysteine nucleosidase (EC 3.2.2.9, a fascinating enzyme that, with a different bound cofactor, acts instead in the pathway of methionine salvage from methylthioadenosine - see TIGR01704) to leave S-ribosylhomocysteine. Next, S-ribosylhomocysteinase acts to produce homocysteine and 4,5-dihydroxypentan-2,3-dione, which cyclizes spontaneously and binds borate to become autoinducer-2 (AI-2), a quorum-sensing molecule produced and recognized by a wide range of bacteria. This property represents the presence at least one of these two mechanisms to regenerate homocysteine. |
| JCVI Role | Sulfur metabolism |
| Parent Property | GenProp0731: amino acid metabolism |
Components
| Step Name | Step Num | Required | Evidence (Method) | Evidence Go Terms |
|---|---|---|---|---|
| SAH to homocysteine | SAH_clv | YES | TIGR00936 (HMM): adenosylhomocysteinaseGenProp0757 (GENPROP): quorum-sensing, autoinducer-2 system | |
| methionine adenosyltransferase | SAM_syn | YES | TIGR01034 (HMM): methionine adenosyltransferase PF01941 (HMM): S-adenosylmethionine synthetase |
Parent Properties
| Accession | Name |
|---|---|
| GenProp0731 | amino acid metabolism |
Sibling Properties
| Accession | Name |
|---|---|
| GenProp0126 | amino acid biosynthesis |
| GenProp0733 | amino acid salvage |
| GenProp0734 | amino acid catabolism |