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An example of a proton pump that is not electrogenic, is the proton/potassium pump of the gastric mucosa which catalyzes a balanced exchange of protons and potassium ions. [citation needed] The combined transmembrane gradient of protons and charges created by proton pumps is called an electrochemical gradient.
This change in both the pH and electrochemical potential gradient between the inside of the cell and the outside produces a proton-motive force, as the protons will want to naturally flow back into the area of low concentration and with a voltage closer to zero from their current situation of being in an area of high concentration of positively ...
-ATPase or proton pump creates the electrochemical gradients in the plasma membrane of plants, fungi, protists, and many prokaryotes. Here, proton gradients are used to drive secondary transport processes. As such, it is essential for the uptake of most metabolites, and also for plant responses to the environment (e.g., movement of leaves).
The gastric hydrogen potassium ATPase or H + /K + ATPase is the proton pump of the stomach.It exchanges potassium from the intestinal lumen with cytoplasmic hydronium [2] and is the enzyme primarily responsible for the acidification of the stomach contents and the activation of the digestive enzyme pepsin [3] (see gastric acid).
The result is the disappearance of a proton from the cytoplasm and the appearance of a proton in the periplasm. Mitochondrial Complex III is this second type of proton pump, which is mediated by a quinone (the Q cycle). Some dehydrogenases are proton pumps, while others are not. Most oxidases and reductases are proton pumps, but some are not.
Furthermore, due to redox-driven proton pumping by coupling sites, the proton gradient is always inside-alkaline. For both of these reasons, protons flow in spontaneously, from the P side to the N side; the available free energy is used to synthesize ATP (see below). For this reason, PMF is defined for proton import, which is spontaneous.
A Proton gradient moves the ions into the vacuole by proton-sodium antiporter or the proton-calcium antiporter. In plants, sucrose transport is distributed throughout the plant by the proton-pump where the pump, as discussed above, creates a gradient of protons so that there are many more on one side of the membrane than the other.
V-ATPases couple the energy of ATP hydrolysis to proton transport across intracellular and plasma membranes of eukaryotic cells. It is generally seen as the polar opposite of ATP synthase because ATP synthase is a proton channel that uses the energy from a proton gradient to produce ATP. V-ATPase however, is a proton pump that uses the energy ...