In a deamination reaction, the nitrogen is removed from the amino acid pool. Deamination could occur in an oxidative way (using reducing cofactors) or in a non-oxidative way (with intramolecular oxidation).
In oxidative deamination, a redox coenzyme (NAD(P), FAD or FMN) is used due to the fact that oxidation means removal of hydrogen, followed by the generation of an H containing molecule. Oxidative deamination occurs through an imino acid intermediate (Figure 1).