AMP deaminase plays a critical role in energy metabolism. Essential for the transition from zygote to embryo. AMP + H(+) + H2O = IMP + NH4(+) Binds 1 zinc ion per subunit. Activated by ATP. Activated by sulfate ions (in vitro). Inhibited by phosphate ions. Purine metabolism; IMP biosynthesis via salvage pathway; IMP from AMP: step 1/1. Homodimer. Interacts with AHK4. Interacts with EER5 (PubMed:19843313). Might be associated with the inner mitochondrial membrane. Expressed in seedlings, roots, leaves, flowers, pollen grains, pollen tubes and siliques, and at a lower level in stems. Expressed in both male and female gametophytes, at the zygote stage, in the endosperm, and during early embryo development. Observed in cotyledonary embryos and in the basal part of the embryo, but not in the suspensor or in mature embryos. Also expressed during somatic embryogenesis. Belongs to the metallo-dependent hydrolases superfamily. Adenosine and AMP deaminases family. Intron retention.