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:2/25/2015)... Ark. , Feb. 25, 2015  ABC ... and billing in the Health and Fitness Industry, ... well as to MYiCLUBonline.  The latest upgrade includes ... the inclusion of cardless check-in via Identity One ... the first time through interactive displays at the ...
(Date:2/23/2015)... , Feb. 23, 2015 NXT-ID, Inc. ... the "Company"), a biometric authentication company focused on the ... filed provisional patent 62114357 for DISTRIBUTED VOICE ... patent, NXT-ID introduces a new groundbreaking payment method. Payment ... payment account may only be accessed if both the ...
(Date:2/12/2015)... , Feb. 12, 2015   MedNet ... specializing in clinical study management systems, has recently ... , further distinguishing iMedNet ... Research Organizations (CROs) and healthcare consultants.  Building on ... prospective customer referrals and numerous co-marketing opportunities), MedNet,s ...
Breaking Biology News(10 mins):ABC Financial Unveils New Software Enhancements 2ABC Financial Unveils New Software Enhancements 3NXT-ID Patents Voice Directed Payments 2NXT-ID Patents Voice Directed Payments 3MedNet Solutions Announces Key Enhancements To Its iMedNet Partner Program 2
... tree of the species known as social amoebas has been ... important clues to the evolution of life on earth. , ... University of York, and biochemist Professor Pauline Schaap, of the ... the 100 or so known species of social amoeba. ...
... What's the difference between a lifeless sack of ... the way they're organized, according to Stanford biophysical ... University of California-Davis and Lawrence Livermore National Laboratory, ... membranes with unprecedented resolution-on the order of 100 ...
... by scientists at the Broad Institute of MIT and Harvard ... "roadmap" that can connect human diseases with potential drugs to ... in human cells. Called the "Connectivity Map," the new tool ... of Science and in separate publications in the September 28 ...
Cached Biology News:Scientists' cell discovery unearths evolutionary clues 2Scientists' cell discovery unearths evolutionary clues 3With record resolution and sensitivity, tool images how life organizes in a cell membrane 2With record resolution and sensitivity, tool images how life organizes in a cell membrane 3With record resolution and sensitivity, tool images how life organizes in a cell membrane 4With record resolution and sensitivity, tool images how life organizes in a cell membrane 5With record resolution and sensitivity, tool images how life organizes in a cell membrane 6Genetic 'roadmap' charts links between drugs and human disease 2Genetic 'roadmap' charts links between drugs and human disease 3
Other biology definitionOther Tags