Homocysteine desulfhydrase

In enzymology, a homocysteine desulfhydrase (EC 4.4.1.2) is an enzyme that catalyzes the chemical reaction

Thus, the two substrates of this enzyme are L-homocysteine and H₂O, whereas its 3 products are hydrogen sulfide, NH₃, and 2-oxobutanoate.

This enzyme belongs to the family of lyases, specifically the class of carbon-sulfur lyases. The systematic name of this enzyme class is L-homocysteine hydrogen-sulfide-lyase (deaminating 2-oxobutanoate-forming). Other names in common use include homocysteine desulfurase, L-homocysteine hydrogen-sulfide-lyase, and (deaminating). This enzyme participates in nitrogen metabolism and sulfur metabolism. It employs one cofactor, pyridoxal phosphate.