air synthetase catalyzes the transfer of the oxygen of the formyl group to phosphate. it is a sequential mechanism in which atp binds first to the enzyme and adp is released last. this enzyme hydrolyzes atp to activate the oxygen of the amide in order to carry out a nucleophilic attack by nitrogen. in humans and many other animals, this enzyme is contained within the trifunctional purine biosynthetic protein adenosine-3 polypeptide.