... both the internal region of exon V that is absent from the inactive PAOh4 isoform, as well as exon VIa, which is absent from the active isoform, SMO ⁄ PAOh1. SMO5 and the active, mouse isoform, ... components of the FAD-bindingdomain, and are therefore essential for catalysis[28,3 3–3 5].Kinetic properties of SMO5Polyamine oxidase activity of SMO5 and SMO ⁄PAOh1 was measured using increasing ... proteins, no homologue of the mousemSMOl, which is essentially a combination of the human isoforms 1 and 4, had been identified. The dis-covery of its existence in the mouse suggested the like-lihood...