Biology:Selenocysteine lyase
| selenocysteine lyase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC number | 4.4.1.16 | ||||||||
| CAS number | 82047-76-5 | ||||||||
| 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 | ||||||||
| |||||||||
The enzyme selenocysteine lyase (SCL) (EC 4.4.1.16) catalyzes the chemical reaction
- L-selenocysteine + reduced acceptor [math]\displaystyle{ \rightleftharpoons }[/math] selenide + L-alanine + acceptor
Nomenclature
This enzyme belongs to the family of lyases, specifically the class of carbon-sulfur lyases. The systematic name of this enzyme class is L-selenocysteine selenide-lyase (L-alanine-forming). Other names in common use include selenocysteine reductase, and selenocysteine β-lyase.
Function
This enzyme participates in selenoamino acid metabolism by recycling Se from selenocysteine during the degradation of selenoproteins, providing an alternate source of Se for selenocysteine biosynthesis.[1]
Structure and mechanism
Mammalian SCL forms a homodimer while bacterial SCL is monomeric. In mammals, highest SCL activity is found in the liver and kidney.[1][2]
While selenocysteine lyases generally catalyze the removal of both selenium or sulfur from selenocysteine or cysteine, respectively, human selenocysteine lyases are specific for selenocysteine. Asp146 has been identified as the key residue that preserves specificity in human SCL.[3]
References
- ↑ 1.0 1.1 "Selenoproteins: molecular pathways and physiological roles". Physiological Reviews 94 (3): 739–77. July 2014. doi:10.1152/physrev.00039.2013. PMID 24987004.
- ↑ "cDNA cloning, purification, and characterization of mouse liver selenocysteine lyase. Candidate for selenium delivery protein in selenoprotein synthesis". The Journal of Biological Chemistry 275 (9): 6195–200. March 2000. doi:10.1074/jbc.275.9.6195. PMID 10692412.
- ↑ "Biochemical discrimination between selenium and sulfur 1: a single residue provides selenium specificity to human selenocysteine lyase". PLOS ONE 7 (1): e30581. 2012. doi:10.1371/journal.pone.0030581. PMID 22295093. Bibcode: 2012PLoSO...730581C.
Further reading
- "Selenocysteine lyase, a novel enzyme that specifically acts on selenocysteine. Mammalian distribution and purification and properties of pig liver enzyme". The Journal of Biological Chemistry 257 (8): 4386–91. April 1982. doi:10.1016/S0021-9258(18)34734-3. PMID 6461656.
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