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Proton pump
 
 
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A proton pump is an integral membrane protein
Integral membrane protein

An Integral Membrane Protein is a protein molecule that is permanently attached to the biological membrane. Such proteins can be separated from the biological membranes only using detergents, nonpolar solvents, or sometimes Denaturation agents....
 that is capable of moving proton
Proton

The proton is a subatomic particle with an electric charge of +1 elementary charge. It is found in the nucleus of each atom but is also stable by itself and has a second identity as the hydrogen ion, H+....
s across the membrane
Cell membrane

The cell membrane is the interface between the cellular machinery inside the cell and the fluid outside.It is a semipermeable lipid bilayer found in all cell ....
 of a cell
Cell (biology)

The cell is the structural and functional unit of all known Life organisms. It is the smallest unit of an organism that is classified as living, and is often called the building bricks of life....
, mitochondrion
Mitochondrion

In cell biology, a mitochondrion is a membrane-enclosed organelle found in most eukaryote cell . These organelles range from 0.5–10 micrometers in diameter....
, or other subcellular compartment.

ell respiration, the pumps grab protons from the matrix
Matrix (biology)

In biology, matrix is the material between animal or plant cell , the material in which more specialized structures are embedded, and a specific part of the mitochondrion that is the site of oxidation of organic molecules....
 (the space enclosed by the two membranes) within the organelle
Organelle

In cell biology, an organelle is a specialized subunit within a cell that has a specific function, and is usually separately enclosed within its own lipid membrane....
 and release the protons into the inter-membrane space.






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Encyclopedia


A proton pump is an integral membrane protein
Integral membrane protein

An Integral Membrane Protein is a protein molecule that is permanently attached to the biological membrane. Such proteins can be separated from the biological membranes only using detergents, nonpolar solvents, or sometimes Denaturation agents....
 that is capable of moving proton
Proton

The proton is a subatomic particle with an electric charge of +1 elementary charge. It is found in the nucleus of each atom but is also stable by itself and has a second identity as the hydrogen ion, H+....
s across the membrane
Cell membrane

The cell membrane is the interface between the cellular machinery inside the cell and the fluid outside.It is a semipermeable lipid bilayer found in all cell ....
 of a cell
Cell (biology)

The cell is the structural and functional unit of all known Life organisms. It is the smallest unit of an organism that is classified as living, and is often called the building bricks of life....
, mitochondrion
Mitochondrion

In cell biology, a mitochondrion is a membrane-enclosed organelle found in most eukaryote cell . These organelles range from 0.5–10 micrometers in diameter....
, or other subcellular compartment.

Function

Proton Gradient
In cell respiration, the pumps grab protons from the matrix
Matrix (biology)

In biology, matrix is the material between animal or plant cell , the material in which more specialized structures are embedded, and a specific part of the mitochondrion that is the site of oxidation of organic molecules....
 (the space enclosed by the two membranes) within the organelle
Organelle

In cell biology, an organelle is a specialized subunit within a cell that has a specific function, and is usually separately enclosed within its own lipid membrane....
 and release the protons into the inter-membrane space. The confined protons create a difference or gradient
Gradient

In vector calculus, the gradient of a scalar field is a vector field which points in the direction of the greatest rate of increase of the scalar field, and whose magnitude is the greatest rate of change....
 in both pH
PH

pH is a measure of the Acid or Base of a solution. It is defined as the cologarithm of the Activity of dissolved hydrogen ions . Hydrogen ion activity coefficients cannot be measured experimentally, so they are based on theoretical calculations....
 and electric charge
Electric charge

Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. Electrically charged matter is influenced by, and produces, electromagnetic fields....
 (ignoring differences in buffer
Buffering agent

A buffering agent adjusts the pH of a solution. The function of a buffering agent is to drive an acidic or basic solution to a certain pH state and prevent a change in this pH....
 capacity) and establish an electrochemical potential
Electrochemical potential

In electrochemistry, the electrochemical potential, , sometimes confusingly abbreviated to ECP, is a thermodynamic measure that combines the concepts of energy stored in the form of chemical potential and electric charge....
 that acts as a kind of battery or reservoir of stored energy for the cell. The inner cell membrane functions in a similar way to a dam in a river. It blocks protons from drifting back into the matrix. Since the pumping action is against the gradient, it requires work
Mechanical work

In physics, mechanical work is the amount of energy transferred by a force acting through a distance. Like energy, it is a scalar quantity, with SI of joules....
 (energy). The process is directly analogous to bicycling uphill or charging a battery (storing up potential energy
Potential energy

Potential energy can be thought of as energy stored within a physical system. It is called potential energy because it has the potential to be converted into other forms of energy, such as kinetic energy, and to do Mechanical work in the process....
). It is important to remember that the proton pump does not create energy. Instead, the gradient stores energy for the appropriate time.

Mobility

Some of the enzymes involved in the electron transport chain
Electron transport chain

An electron transport chain couples a chemical reaction between an electron donor and an electron acceptor to the transfer of proton across a Cell membrane, through a set of mediating biochemical reactions....
, such as ubiquinone, travel along the matrix, like freight boats, navigating up and down the river.

Others such as NADH-Q reductase
Reductase

A reductase is an enzyme which lowers the activation energy for a Redox. ...
, act like ferryboats and cross the matrix. Enzymes that can cross the matrix may have a secondary role as proton pumps because they can deliver protons to the inner membrane.

Diversity


In Eukaryotes

In mitochondria, reducing equivalents
Electrochemistry

Electrochemistry is a branch of chemistry that studies chemical reactions which take place in a solution at the interface of an electron Electrical conductor and an ionic conductor , and which involve electron transfer between the electrode and the electrolyte or species in solution....
 provided by electron transfer or photosynthesis
Photosynthesis

File:Seawifs global biosphere.jpgPhotosynthesis is a metabolic pathway that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight....
 power this translocation of protons. For example, the translocation of protons by cytochrome c oxidase
Cytochrome c oxidase

The enzyme cytochrome c oxidase or Complex IV is a large transmembrane protein complex found in bacteria and the mitochondrion.It is the last enzyme in the respiratory electron transport chain of mitochondria located in the mitochondrial membrane....
 is powered by reducing equivalents provided by reduced cytochrome c
Cytochrome c

Cytochrome c, or cyt c is a small heme protein found loosely associated with the inner membrane of the mitochondrion. It belongs to the cytochrome c family of proteins....
. In the plasma membrane proton ATPase and in the ATPase proton pumps of other cellular membranes, ATP itself powers this transport.

The FoF1 ATP synthase
ATP synthase

An ATP synthase is a general term for an enzyme that can synthesize adenosine triphosphate from adenosine diphosphate and inorganic phosphate by using some form of energy....
 of mitochondria, in contrast, usually conduct protons from high to low concentration across the membrane while drawing energy from this flow to synthesize ATP. To allow the passage of protons a proton channel
Ion channel

Ion channels are pore-forming proteins that help establish and control the small voltage gradient across the plasma membrane of all living cell s by allowing the flow of ions down their electrochemical gradient....
 temporarily opens in the inner membrane.

In Prokaryotes

In bacteria and other ATP-producing organelles than mitochondria, ATP-producing organelles, reducing equivalents
Electrochemistry

Electrochemistry is a branch of chemistry that studies chemical reactions which take place in a solution at the interface of an electron Electrical conductor and an ionic conductor , and which involve electron transfer between the electrode and the electrolyte or species in solution....
 provided by electron transfer or photosynthesis
Photosynthesis

File:Seawifs global biosphere.jpgPhotosynthesis is a metabolic pathway that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight....
 power the translocation of protons.

CF1 ATP ligase
Ligase

In biochemistry, a ligase is an enzyme that can catalyse the joining of two large molecules by forming a new chemical bond, usually with accompanying hydrolysis of a small chemical group pendant to one of the larger molecules....
 of chloroplast
Chloroplast

Chloroplasts are organelles found in plant cells and other eukaryote organisms that conduct photosynthesis. Chloroplasts capture light energy to conserve Thermodynamic free energy in the form of Adenosine triphosphate and reduce NADP to NADPH through a complex set of processes called photosynthesis....
s correspond to the human FoF1 ATP synthase in plants.

Bacteriorhodopsin
Bacteriorhodopsin

Bacteriorhodopsin is a protein used by archaea, most notably halobacteria. It acts as a proton pump, i.e. it captures light energy and uses it to move protons across the membrane out of the cell....
 is a photosynthetic
Photosynthesis

File:Seawifs global biosphere.jpgPhotosynthesis is a metabolic pathway that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight....
 pigment
Pigment

A pigment is a material that changes the color of light it Reflection as the result of selective color absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which the material itself emits light....
 used by archaea
Archaea

The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon . Archaea, like bacteria, are prokaryotic....
, most notably halobacteria
Halobacteria

In alpha taxonomy, the Halobacteria are a class of the Euryarchaeota, found in water saturated or nearly saturated with salt. They are also called halophiles, though this name is also used for other organisms which live in somewhat less concentrated salt water....
.

See also


  • transmembrane ATPase
  • active transport
    Active transport

    Active transport is the mediated process of moving particles across a biological membrane against a Concentration_gradient#In_biology . If the process uses chemical energy, such as from adenosine triphosphate , it is termed primary active transport....
  • cytochrome
    Cytochrome

    Cytochromes are, in general, membrane-bound hemoproteins that contain heme groups and carry out electron transport.They are found either as subunitss or as subunits of bigger enzymatic complexes that catalyze redox reactions....
  • mitochondrion
    Mitochondrion

    In cell biology, a mitochondrion is a membrane-enclosed organelle found in most eukaryote cell . These organelles range from 0.5–10 micrometers in diameter....
  • chloroplast
    Chloroplast

    Chloroplasts are organelles found in plant cells and other eukaryote organisms that conduct photosynthesis. Chloroplasts capture light energy to conserve Thermodynamic free energy in the form of Adenosine triphosphate and reduce NADP to NADPH through a complex set of processes called photosynthesis....
  • electron transfer chain
  • proton pump inhibitor
    Proton pump inhibitor

    Proton pump inhibitors are a group of Medications whose main action is a pronounced and long-lasting reduction of gastric acid production. They are the most potent inhibitors of acid secretion available today....
  • ATP synthase
    ATP synthase

    An ATP synthase is a general term for an enzyme that can synthesize adenosine triphosphate from adenosine diphosphate and inorganic phosphate by using some form of energy....
  • V-ATPase
    V-ATPase

    Vacuolar type H+-ATPase is a highly conserved evolutionarily ancient enzyme with remarkably diverse functions in Eukaryote organisms. V-ATPases acidifiy a wide array of intracellular organelles and proton pump across the Cell membrane of numerous cell types....
  • GORD
    Gord

    Gord may refer to:* GORD, gastro-oesophageal reflux disease, mucosal damage produced by the abnormal reflux of gastric contents into the oesophagus...
  • Kidney
    Kidney

    The kidneys are Organ that have numerous biological roles. Their primary role is to maintain the homeostasis balance of bodily fluids by filtering and secreting Metabolomics#Metabolitess and minerals from the blood and excreting them, along with water , as urine....
  • proton ATPase
    Proton ATPase

    H+-ATPase is also known as Proton ATPase and Proton pump....


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