Cystathionine beta-lyase

In enzymology, a cystathionine beta-lyase is an enzyme that catalyzes the chemical reaction


 * L-cystathionine + H2O $$\rightleftharpoons$$ L-homocysteine + NH3 + pyruvate

Thus, the two substrates of this enzyme are L-cystathionine and H2O, whereas its 3 products are L-homocysteine, NH3, and pyruvate.

This enzyme 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). Other names in common use include beta-cystathionase, cystine lyase, cystathionine L-homocysteine-lyase (deaminating), and L-cystathionine L-homocysteine-lyase (deaminating). This enzyme participates in 5 metabolic pathways: methionine metabolism, cysteine metabolism, selenoamino acid metabolism, nitrogen metabolism, and sulfur metabolism. It employs one cofactor, pyridoxal phosphate.

Structural studies
As of late 2007, 5 structures have been solved for this class of enzymes, with PDB accession codes, , , , and.