Metabolism is the sum total of anabolism and catabolism. ATP acts as a bridge between catabolism and anabolism. Usually, catabolism releases energy, and anabolism consumes energy. These last two points suggest a connection between pyrimidine anabolism and oxidative catabolism. This allows a switch between catabolism and anabolism. In this way, possible cycles of opposite anabolism and catabolism reactions are avoid. This is like the forces of anabolism and catabolism in the human body. Aerobic glycolysis favors anabolism and avoids oxidizing precious carbon-carbon bonds into carbon dioxide. Protein anabolism is the process by which protein are formed from amino acids. There is evidence that hyperaminoacidemia increases protein synthesis and anabolism. Catabolism is the breaking-down aspect of metabolism, whereas anabolism is the building-up aspect. Porphyrin synthesis (i.e., heme anabolism) is highly conserved across all domains of life. Next, the body tries to replenish its energy stores of glucose and protein via anabolism. The first is anabolism, which refers to the buildup of molecules. Catabolism breaks down molecules, and anabolism puts them together.