In enzymology, an adenosylcobyric acid synthase (glutamine-hydrolysing) () is an enzyme that catalyzes the chemical reaction
The four substrates of this enzyme are ATP, adenosylcobyrinic acid a,c-diamide, L-glutamine, and H<sub>2</sub>O; its four products are ADP, phosphate, adenosylcobyric acid, and L-glutamate.
This enzyme belongs to the family of ligases, specifically those forming carbon-nitrogen bonds carbon-nitrogen ligases with glutamine as amido-N-donor (Glutamine amidotransferases). The systematic name of this enzyme class is adenosylcobyrinic-acid-a,c-diamide:L-glutamine amido-ligase (ADP-forming). This enzyme is part of the biosynthetic pathway to cobalamin (vitamin B<sub>12</sub>) in bacteria.