| cystathionine beta-lyase | |||||||||
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Cystathionine beta-lyase tetramer, E.Coli
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| Identifiers | |||||||||
| EC number | 4.4.1.8 | ||||||||
| CAS number | 9055-05-4 | ||||||||
| 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 / EGO | ||||||||
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| Search | |
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| PMC | articles |
| PubMed | articles |
| NCBI | proteins |
Cystathionine beta-lyase (EC 4.4.1.8), also commonly referred to as CBL or β-cystathionase, is an enzyme that primarily catalyzes the following α,β-elimination reaction
Thus, the substrate of this enzyme is L-cystathionine, whereas its 3 products are homocysteine, pyruvate, and ammonia.
Found in plants, bacteria, and yeast, cystathionine beta-lyase is an essential part of the methionine biosynthesis pathway as homocysteine can be directly converted into methionine by methionine synthase. The enzyme belongs to the γ-family of PLP-dependent enzymes due to its use of a pyridoxal-5'-phosphate (PLP) cofactor to cleave cystathionine. The enzyme also belongs to the family of lyases, specifically the class of carbon-sulfur lyases. The systematic name of this enzyme class is L-cystathionine L-homocysteine-lyase (deaminating; pyruvate-forming). This enzyme participates in 5 metabolic pathways: methionine metabolism, cysteine metabolism, selenoamino acid metabolism, nitrogen metabolism, and sulfur metabolism.