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Adenosine triphosphate
Adenosine triphosphate
Adenosine diphosphate
Adenosine diphosphate

ATPases are a class of enzymes that catalyze the decomposition of adenosine triphosphate (ATP) into adenosine diphosphate (ADP) and a free phosphate ion. Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy Adenosine diphosphate, abbreviated ADP, is a Nucleotide. It is an Ester of Pyrophosphoric acid with the Nucleoside Adenosine Enzymes are Biomolecules that catalyze ( ie increase the rates of Chemical reactions Almost all enzymes are Proteins Catalysis is the process in which the rate of a Chemical reaction is increased by means of a Chemical substance known as a catalyst Decomposition (or spoilage) refers to the break down of tissue of a formerly living Organism into simpler forms of matter Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy Adenosine diphosphate, abbreviated ADP, is a Nucleotide. It is an Ester of Pyrophosphoric acid with the Nucleoside Adenosine A phosphate, an Inorganic chemical, is a salt of Phosphoric acid. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge This dephosphorylation reaction releases energy, which the enzyme (in most cases) harnesses to drive other chemical reactions that would not otherwise occur. Dephosphorylation is the essential process of removing Phosphate groups from an Organic compound (as ATP) by Hydrolysis. In Physics and other Sciences energy (from the Greek grc ἐνέργεια - Energeia, "activity operation" from grc ἐνεργός A chemical reaction is a process that always results in the interconversion of Chemical substances The substance or substances initially involved in a chemical reaction are called This process is widely used in all known forms of life. Life is a state that distinguishes Organisms from non-living objects such as non-life and dead organisms being manifested by growth through Metabolism

Some such enzymes are integral membrane proteins (anchored within biological membranes), and move solutes across the membrane. An Integral Membrane Protein ( IMP) is a Protein Molecule (or assembly of proteins that is permanently attached to the Biological membrane. MembraneA biological membrane or biomembrane is an enclosing or separating Amphipathic layer that acts as a barrier within or around a cell. In Chemistry, a solution is a Homogeneous Mixture composed of two or more substances (These are called transmembrane ATPases).

Contents

Functions

Na+/K+ATPase
Na+/K+ATPase

Transmembrane ATPases import many of the metabolites necessary for cell metabolism and export toxins, wastes, and solutes that can hinder cellular processes. The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called Metabolism is the set of Chemical reactions that occur in living Organisms in order to maintain Life. An important example is the sodium-potassium exchanger (or Na+/K+ATPase), which establishes the ionic concentration balance that maintains the cell potential. The Membrane potential, or better Membrane Voltage, is the difference of Electric potentials between two Aqueous solutions separated by a ( Another example is the hydrogen potassium ATPase (H+/K+ATPase or gastric proton pump) that acidifies the contents of the stomach. Gastric hydrogen potassium ATPase is also known as H+/K+ ATPase Function and location The gastric hydrogen potassium ATPase or

Besides exchangers, other categories of transmembrane ATPase include co-transporters and pumps (however, some exchangers are also pumps). Co-transport, also known as coupled transport refers to the simultaneous or sequential passive transfer of Molecules or Ions across Biological membranes in 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.

Mechanism

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 out of the cell and 2 K+ ions inward 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. In Physics, mechanical work is the amount of Energy transferred by a Force. In Physics, thermodynamics (from the Greek θερμη therme meaning " Heat " and δυναμις dynamis meaning " This process is considered active transport. Active transport is the mediated process of moving particles across Biological membrane against the concentration gradient

For example, the blocking of the vesicular H+-ATPAses would increase the pH inside vesicles and decrease the pH of the cytoplasm.

Transmembrane ATP synthases

Main article: ATP synthase

The 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). An ATP synthase ( is a general term for an Enzyme that can synthesize Adenosine triphosphate (ATP from Adenosine diphosphate (ADP and inorganic An ATP synthase ( is a general term for an Enzyme that can synthesize Adenosine triphosphate (ATP from Adenosine diphosphate (ADP and inorganic In Cell biology, a mitochondrion (plural mitochondria) is a membrane-enclosed Organelle found in most eukaryotic cells. Chloroplasts are Organelles found in Plant cells and eukaryotic Algae that conduct Photosynthesis. Anabolism is the set of Metabolic pathways that construct molecules from smaller units The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive A phosphate, an Inorganic chemical, is a salt of Phosphoric acid. Adenosine diphosphate, abbreviated ADP, is a Nucleotide. It is an Ester of Pyrophosphoric acid with the Nucleoside Adenosine

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 synthase can also function in reverse, that is, use energy released by ATP hydrolysis to pump protons against their thermodynamic gradient.

Classification

There are different types of ATPases, which can differ in function (ATP synthesis and/or hydrolysis), structure (F-, V- and A-ATPases contain rotary motors) and in the type of ions they transport.

P-ATPase

Main article: P-ATPase

P-ATPases (sometime known as E1-E2 ATPases) are found in bacteria and in a number of eukaryotic plasma membranes and organelles. P-type (or E1-E2-type ATPases constitute a superfamily of cation transport enzymes present both in prokaryota and eukaryota whose members mediate membrane flux of all common biologically P-type (or E1-E2-type ATPases constitute a superfamily of cation transport enzymes present both in prokaryota and eukaryota whose members mediate membrane flux of all common biologically P-ATPases function to transport a variety of different compounds, including ions and phospholipids, across a membrane using ATP hydrolysis for energy. There are many different classes of P-ATPases, each of which transports a specific type of ion: H+, Na+, K+, Mg2+, Ca2+, Ag+ and Ag2+, Zn2+, Co2+, Pb2+, Ni2+, Cd2+, Cu+ and Cu2+. Calcium ATPase is a form of P-ATPase which transfers Calcium after a Muscle has contracted P-ATPases can be composed of one or two polypeptides, and can usually assume two main conformations called E1 and E2.

Human genes

See also

Additional images

AAA+ ATPases (three examples)

External links

Calcium ATPase is a form of P-ATPase which transfers Calcium after a Muscle has contracted Gastric hydrogen potassium ATPase is also known as H+/K+ ATPase Function and location The gastric hydrogen potassium ATPase or Vacuolar type H+-ATPase ( V-ATPase) is a highly conserved evolutionarily ancient Enzyme with remarkably diverse functions in eukaryotic organisms ATP7A ( ATPase Cu++ transporting alpha polypeptide (Menkes syndrome) is a Human Gene that provides instructions to make a Protein that Wilson disease protein (also called ATP7B) is an ATPase that transports Copper. An ATP synthase ( is a general term for an Enzyme that can synthesize Adenosine triphosphate (ATP from Adenosine diphosphate (ADP and inorganic ATPases (or ATP synthases are membrane-bound enzyme complexes/ Ion transporters that combine ATP synthesis and/or hydrolysis with the AAA or AAA+ is an abbreviation for ATPases Associated with diverse cellular Activities. P-type (or E1-E2-type ATPases constitute a superfamily of cation transport enzymes present both in prokaryota and eukaryota whose members mediate membrane flux of all common biologically Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books Orientations of Proteins in Membranes (OPM database provides spatial positions of protein three-dimensional structures with respect to the Lipid bilayer. Orientations of Proteins in Membranes (OPM database provides spatial positions of protein three-dimensional structures with respect to the Lipid bilayer.
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