IMP dehydrogenase catalyzes the reaction that follows:
Inosine Monophosphate (IMP) + NAD+ + H2O <=> Xanthosine Monophosphate (XMP) + NADH + H+
The reaction is part of the de novo biosynthetic pathway of purines. IMP dehydrogenase is allosterically inhibited by GMP, the end product of the pathway.