Control of the catalytic activity by feedback regulation is a crucial process providing the regulation of multiple metabolic pathways. The regulation is based on the principle that the products of the catalysis inhibit the reaction or specific biochemical pathways. As a result, the final product also serves as an allosteric regulator of the enzyme that mediates the reaction or provides the initial reaction in the current metabolic pathway. For example, ATP is the final product of cellular respiration. Production of ATP involves several biochemical pathways, including glycolysis, citric acid cycle, and mitochondria respiratory chain. All these pathways are mediated by multiple enzymes directly controlled by the level of ATP. As a result, increased production of ATP may inhibit the activity of the enzymes that decrease the overall ATP synthesis. This type of catalytic regulation maintains the energetic balance of cells triggering the production of ATP when its levels decrease.