Cystathionine gamma-lyase

Cystathionine gamma-lyase (or cystathionase) is an enzyme which breaks down cystathionine into cysteine and α-ketobutyrate. Pyridoxal phosphate is a prosthetic group of this enzyme.

Cystathionine gamma-lyase also catalyses the following elimination reactions:
 * L-homoserine to form H2O, NH3 and 2-oxobutanoate
 * L-cystine, producing thiocysteine, pyruvate and NH3
 * L-cysteine producing pyruvate, NH3 and H2S

In some bacteria and mammals, including humans, this enzyme takes part in generating hydrogen sulfide.

Examples
The following cystathionine gamma-lyase is expressed in humans:

Pathology
An deficiency is associated with cystathioninuria.