Catabolism of Proteins and Amino Acids

In addition to containing carbohydrates and fats, diets may be rich in proteins. The catabolism of proteins results in the generation of their component parts, amino acids. When the dietary amino acid requirements of an individual are satisfied, the excess amino acids in the diet are catabolized to CO₂ and water as a source of energy. Some amino acids are degraded to molecules that feed directly into glycolysis, and others result in the production of acetyl CoA. Excess nitrogen resulting from the catabolism of amino acids and other compounds that contain nitrogen is excreted in mammals in urine in the form of the simple organic compound urea. Some amino acids are precursors in the biosynthesis of other organic molecules.