ATP Synthase

ATPases are a class of enzymes that catalyze the decompositionof ATP into ADP and a free phosphate ion. This dephosphorylation reaction releases energy, which the enzyme (in most cases) harnesses to drive other chemical reactions that would not otherwise occur. Some such enzymes are integral membrane proteins and move solutes across the membrane, typically against their concentration gradient. These are called transmembrane ATPases. Transmembrane ATPases import many of the metabolites necessary for cell metabolism and export toxins, wastes, and solutes that can hinder cellular processes. Such as the sodium-potassium exchanger (or Na⁺/K⁺ ATPase) and the hydrogen potassium ATPase (H⁺/K⁺ ATPase or gastric proton pump) that acidifies the contents of the stomach.