KEGG   ENZYME: 4.4.1.28Help
Entry
EC 4.4.1.28                 Enzyme                                 

Name
L-cysteine desulfidase;
L-cysteine desulfhydrase
Class
Lyases;
Carbon-sulfur lyases;
Carbon-sulfur lyases (only sub-subclass identified to date)
BRITE hierarchy
Sysname
L-cysteine sulfide-lyase (deaminating; pyruvate-forming)
Reaction(IUBMB)
L-cysteine + H2O = sulfide + NH3 + pyruvate (overall reaction) [RN:R00782];
(1a) L-cysteine = 2-aminoprop-2-enoate + sulfide;
(1b) 2-aminoprop-2-enoate = 2-iminopropanoate (spontaneous);
(1c) 2-iminopropanoate + H2O = pyruvate + NH3 (spontaneous)
Reaction(KEGG)
Substrate
L-cysteine [CPD:C00097];
H2O [CPD:C00001];
2-aminoprop-2-enoate [CPD:C02218];
2-iminopropanoate [CPD:C20904]
Product
sulfide [CPD:C00283];
NH3 [CPD:C00014];
pyruvate [CPD:C00022];
2-aminoprop-2-enoate [CPD:C02218];
2-iminopropanoate [CPD:C20904]
Comment
The enzyme from the archaeon Methanocaldococcus jannaschii contains a [4Fe-4S] cluster and is specific for L-cysteine (cf. EC 4.4.1.1, cystathionine gamma-lyase). It cleaves a carbon-sulfur bond releasing sulfide and the unstable enamine product 2-aminoprop-2-enoate that tautomerizes to an imine form, which undergoes a hydrolytic deamination to form pyruvate and ammonia. The same reaction can also be catalysed by some pyridoxal-phosphate proteins (cf. EC 4.4.1.1, cystathionine gamma-lyase).
History
EC 4.4.1.28 created 2014
Pathway
Cysteine and methionine metabolism
Orthology
K20021  
L-cysteine desulfidase
Genes
MJA: 
MFE: 
MVU: 
MFS: 
MIF: 
MJH: 
MIG: 
MMP: 
MMQ: 
MMX: 
MMZ: 
MMD: 
MMAK: 
MMAO: 
 » show all
Taxonomy
Reference
1  [PMID:15683250]
  Authors
Tchong SI, Xu H, White RH
  Title
L-cysteine desulfidase: an [4Fe-4S] enzyme isolated from Methanocaldococcus jannaschii that catalyzes the breakdown of L-cysteine into pyruvate, ammonia, and sulfide.
  Journal
Biochemistry. 44 (2005) 1659-70.
  Sequence
[mja:MJ_1025]
Other DBs
ExplorEnz - The Enzyme Database: 
IUBMB Enzyme Nomenclature: 
ExPASy - ENZYME nomenclature database: 
BRENDA, the Enzyme Database: 

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