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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.
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).
-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).
Proton pump inhibitors are prodrugs and their actual inhibitory form is somewhat controversial. In acidic solution, the sulfenic acid is isolated before reaction with one or more cysteines accessible from the luminar surface of the enzyme, a tetracyclic sulfenamide. This is a planar molecule thus any enantiomer of a PPI loses stereospecifity ...
This ion pump uses ATP to pump three sodium ions out of the cell and two potassium ions into the cell, creating an electrochemical gradient and electromotive force across the cell membrane. The highly selective potassium ion channels (which are tetramers ) are crucial for hyperpolarization inside neurons after an action potential is triggered ...
The proton pump is the terminal stage in gastric acid secretion, being directly responsible for secreting H + ions into the gastric lumen, making it an ideal target for inhibiting acid secretion. [ citation needed ] Because the H,K-ATPase is the final step of acid secretion, an inhibitor of this enzyme is more effective than receptor ...
The yeast V-ATPase is the best characterized. There are at least thirteen subunits identified to form a functional V-ATPase complex, which consists of two domains. The subunits belong to either the V o domain (membrane associated subunits, lowercase letters on the figure) or the V 1 domain (peripherally associated subunits, uppercase letters on the figure).
The discovery of proton pumps in the CV membrane [3] and the direct measurement of ion concentrations inside the CV using microelectrodes [4] led to the following model: the pumping of protons either into or out of the CV causes different ions to enter the CV.