text: When a plant or animal dies or an animal expels waste, the initial form of nitrogen is organic. Bacteria or fungi convert the organic nitrogen within the remains back into ammonium (), a process called ammonification or mineralization. Enzymes involved are:
  * GS: Gln Synthetase (cytosolic & plastic)
  * GOGAT: Glu 2-oxoglutarate aminotransferase (Ferredoxin & NADH-dependent)
  * GDH: Glu Dehydrogenase:
  ** Minor role in ammonium assimilation.
  ** Important in amino acid catabolism.