The primary reason for protein catabolism is so organisms can convert proteins into a form of energy that the body can use. To reuse their proteins, bacteria or soil microorganisms break down their proteins through protein catabolism into their individual amino acids and are used to form bacterial proteins or oxidized for energy. To convert to energy, once the proteins are broken down, they are typically deaminated (removal of an amino group) so that they can be processed into the Krebs/Citric Acid (TCA) Cycle. By proceeding into the Citric Acid Cycle, the original proteins will be converted into usable energy for the organism.