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Some such enzymes are integral membrane proteins (anchored within biological membranes), and move solutes across the membrane. (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. An important example is the sodium-potassium exchanger (or Na⁺/K⁺ATPaseNaKATPase (also known as the Na+/K+ pump or Na+/K+ exchanger is an enzyme ( EC ) located in the plasma membrane (specifically an electrogenic transmembrane ATPase). It is found in the plasma membrane of virtually every human cell and is common to all cell), which establishes the ionic concentration balance that maintains the cell potentialIn biological cells that are electrically "at rest," the cytosol possesses a uniform electric potential or voltage compared to the extracellular solution. This voltage is the resting cell potential also sometimes called the transmembrane potential of the.

Besides exchangers, other categories of transmembrane ATPase include cotransporters and pumps (however, some exchangers are also pumps). Some of these, like the Na⁺/K⁺ATPase, cause a net flow of charge, but others do not. These are called "electrogenic" and "nonelectrogenic" transporters, respectively.

The coupling between ATP hydrolysis and transport is more or less a strict chemical reaction, in which a fixed number of solute molecules are transported for each ATP molecule that is hydrolyzed; for example, 3 Na⁺ ions inward and 2 K⁺ ions outward per ATP hydrolyzed, for the Na⁺/K⁺ exchanger.

Transmembrane ATPases harness the chemical potential energy of ATP, because they perform mechanical workWork (abbreviated W is the energy transferred in applying force over a distance. Work can be calculated from the formula: : : where F is the force. s is the position. Readers not familiar with vectors and calculus please see "Simpler Formulae" below.: they transport solutes in a direction opposite to their thermodynamically preferred direction of movement—that is, from the side of the membrane where they are in low concentration to the side where they are in high concentration. This process is considered active transportIn cell biology, active transport is the mediated transport of biochemicals, and other atomic/ molecular substances, across membranes. Unlike passive transport, this process requires chemical energy. In this form of transport, molecules move against eithe.

1 ATP synthetase

The ATP synthetase (or ATP synthaseAn ATP synthase is a general term for an enzyme that can synthesize adenosine triphosphate (ATP) from adenosine diphosphate (ADP) and inorganic phosphate by utilizing some form of energy. The overall reaction sequence is: :ADP + P → ATP These enzymes) of mitochondria and chloroplastChloroplasts are organelles found in plant cells and eukaryotic algae which conduct photosynthesis. Chloroplasts are similar to mitochondria but are found only in plants. Both organelles are surrounded by a double membrane with an intermembrane space; bots is an anabolic enzyme that harnesses the energy of a transmembrane proton gradient as an energy source for adding an inorganic phosphate group to a molecule of adenosine diphosphate (ADP) to form a molecule of adenosine triphosphate (ATP). This enzyme works when a proton moves down the concentration gradient, giving the enzyme a spinning motion. This unique spinning motion bonds ADP and P together to create ATP. ATP synthetase can also function in reverse; that is, use energy released by ATP hydrolysis to pump protons against their thermodynamic gradient.