In enzymology, a dethiobiotin synthase () is an enzyme that catalyzes the chemical reaction
The 3 substrates of this enzyme are ATP, 7,8-diaminononanoate, and CO<sub>2</sub>, whereas its 3 products are ADP, phosphate, and dethiobiotin.
This enzyme belongs to the family of ligases, specifically the cyclo-ligases, which form carbon-nitrogen bonds. The systematic name of this enzyme class is 7,8-diaminononanoate:carbon-dioxide cyclo-ligase (ADP-forming). This enzyme is also called desthiobiotin synthase. This enzyme participates in biotin metabolism.
As of late 2007, 14 structures have been solved for this class of enzymes, with PDB accession codes , , , , , , , , , , , , , and .