Navigation Links
ATPase


ATPases are a class of enzymes that catalyze the decomposition of adenosine triphosphate (ATP) into adenosine diphosphate (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. This process is widely used in all known forms of life.

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+ATPase), which establishes the ionic concentration balance that maintains the cell potential.

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 work: 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 transport.

ATP synthetase

The ATP synthetase (or ATP synthase) of mitochondria and chloroplasts 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.

External links


'"/>


(Date:11/7/2014)... CORAL SPRINGS, Florida , November 6, 2014 ... improved secure authentication for better mobile security revolutionizing online transactions. ... NXTD ), Alibaba Holdings Ltd. (NYSE: BABA ), ... MSFT ), eBay Inc. (NASDAQ: EBAY ... (NASDAQ: NXTD and NXTDW), a biometric authentication ...
(Date:11/5/2014)... of biology in the UTSA College of Sciences, ... selected to receive a two-year $300,00 National Science ... (EAGER). The funding supports President Obama,s BRAIN Initiative, ... new technology that will demystify complex brain processes. ... neuroscience are broken into the interactions of multiple ...
(Date:11/4/2014)... – Temple University School of Medicine announced today ... an initiative funded by the Bill & Melinda ... of Obstetrics, Gynecology and Reproductive Sciences; and Vice ... University School of Medicine will pursue an innovative ... Blood Biomarkers to Assess Fetal Neurodevelopment.", Grand Challenges ...
Breaking Biology News(10 mins):Universal Authentication Methods Provide More Secure Operations for Biometrics Devices - Company Joins FIDO Alliance for Consumer Protection 2Universal Authentication Methods Provide More Secure Operations for Biometrics Devices - Company Joins FIDO Alliance for Consumer Protection 3Universal Authentication Methods Provide More Secure Operations for Biometrics Devices - Company Joins FIDO Alliance for Consumer Protection 4Universal Authentication Methods Provide More Secure Operations for Biometrics Devices - Company Joins FIDO Alliance for Consumer Protection 5Universal Authentication Methods Provide More Secure Operations for Biometrics Devices - Company Joins FIDO Alliance for Consumer Protection 6UTSA biology professor awarded $300,000 NSF grant for brain research 2UTSA biology professor awarded $300,000 NSF grant for brain research 3Temple University School of Medicine receives Grand Challenges Explorations grant 2
... at the University of Wisconsin-Madison may represent a significant ... that would use this abundant element to store and ... non-carbon, non-polluting fuel for storing intermittent energy from the ... water but no carbon dioxide. Practically speaking, producing hydrogen ...
... U.S. Department of Energy,s Brookhaven National Laboratory have identified ... human adenovirus, a cause of ailments ranging from colds ... in FEBS Letters , a journal of the ... sifted through thousands of compounds to determine which might ...
... have alteration in metabolic pathways as a result of ... 2-related factor 2) works as a "master gene" that ... pollutant-detoxifying genes to protect the lungs from variety of ... However, researchers at the Johns Hopkins Bloomberg School of ...
Cached Biology News:New catalyst could cut cost of making hydrogen fuel 2Scientists identify promising antiviral compounds 2Scientists identify promising antiviral compounds 3Hijacking stress response in cancer 2
Other biology definitionOther Tags