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A new class EC 7, Translocases, has been added to the EC list. It will be part of ENZYME from release 2018_10. Read more about EC 7 here.

ENZYME entry: EC 4.4.1.8

Accepted Name
Cystathionine beta-lyase.
Alternative Name(s)
Beta C-S lyase.
Beta-cystathionase.
Cysteine lyase.
Cystine lyase.
Reaction catalysed
L-cystathionine + H(2)O <=> L-homocysteine + NH(3) + pyruvate
Cofactor(s)
Pyridoxal 5'-phosphate.
Comment(s)
  • The enzyme cleaves a carbon-sulfur bond, releasing L-homocysteine and an unstable enamine product that tautomerizes to an imine form, which undergoes a hydrolytic deamination to form pyruvate and ammonia.
  • The latter reaction, which can occur spontaneously, can also be catalyzed by EC 3.5.99.10.
  • The enzyme from some sources also acts on L-cystine, forming pyruvate, ammonia and cysteine persulfide, and a number of related compounds.
  • Possibly identical, in Saccharomyces cerevisiae, with EC 4.4.1.6.
Cross-references
PROSITEPDOC00518 ; PDOC00677
BRENDA4.4.1.8
EC2PDB4.4.1.8
ExplorEnz4.4.1.8
PRIAM enzyme-specific profiles4.4.1.8
KEGG Ligand Database for Enzyme Nomenclature4.4.1.8
IUBMB Enzyme Nomenclature4.4.1.8
IntEnz4.4.1.8
MEDLINEFind literature relating to 4.4.1.8
MetaCyc4.4.1.8

View entry in original ENZYME format
View entry in raw text format (no links)
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 4.4.1.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 4.4.-.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 4.-.-.-