Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. In enzymology, a selenocysteine lyase (EC 4.4.1.16) is an enzyme that catalyzes the chemical reaction L-selenocysteine + reduced acceptor rightleftharpoons selenide + L-alanine + acceptor. Thus, the two substrates of this enzyme are L-selenocysteine and reduced acceptor, whereas its 3 products are selenide, L-alanine, and acceptor. This enzyme belongs to the family of lyases, specifically the class of carbon-sulfur lyases. The systematic name of this enzyme class is L-selenocysteine selenide-lyase (L-alanine-forming).