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Difference between revisions of "Adenine nucleotides"

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{{MitoPedia
{{MitoPedia
|abbr=AN
|abbr=AN
|description='''Adenine nucleotides''' are a group of organic molecules including AMP, [[ADP]] and [[ATP]]. These molecules present the major players of energy storage and transfer. Their structures comprise the purine base adenine, a five-carbon sugar and one to three phosphate groups.
|description='''Adenine nucleotides''', which are also sometimes referred to as adenosines or adenylates, are a group of organic molecules including AMP, [[ADP]] and [[ATP]]. These molecules present the major players of energy storage and transfer.
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{{MitoPedia concepts}}
{{MitoPedia concepts}}
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== Adenine nucleotides and energy transfer ==
== Adenine nucleotides and energy transfer ==


Adenine nucleotides, which are also sometimes referred to as adenosines or adenylates, have the typical structure of nucleotides but feature an additional adenine, which is attached to the ribose sugar moiety of the nucleotide. The three best known members of this family are the purine nucleotides AMP, [[ADP]] and [[ATP]], which can be converted into each other by the addition or removal of one to two [[phosphate]] groups. This process stores or releases energy and is thereby essential for energy transfer and supply of multiple cellular reactions. The breaking of one phosphoanhydride bond releases 30.5 kJ/mol of energy. Thus, the dephosphorylation of the energy-rich [[ATP]] to [[ADP]] yields a free energy of 30.5 kJ/mol or even 61 kJ/mol when two phosphate groups are released (as shown below).
Adenine nucleotides have the typical structure of nucleotides including the purine base adenine attached to a five-carbon sugar and one to three phosphate groups. The three best known members of this family are the purine nucleotides AMP, [[ADP]] and [[ATP]], which can be converted into each other by the addition or removal of one to two [[phosphate]] groups. This process stores or releases energy and is thereby essential for energy transfer and supply of multiple cellular reactions. The breaking of one phosphoanhydride bond releases 30.5 kJ/mol of energy. Thus, the dephosphorylation of the energy-rich [[ATP]] to [[ADP]] yields a free energy of 30.5 kJ/mol or even 61 kJ/mol when two phosphate groups are released (as shown below).


:* ATP + H<sub>2</sub>O β†’ ADP + P<sub>i</sub> &emsp; &emsp; &emsp; Ξ”G = -30.5 kJ/mol
:* ATP + H<sub>2</sub>O β†’ ADP + P<sub>i</sub> &emsp; &emsp; &emsp; Ξ”G = -30.5 kJ/mol

Revision as of 18:58, 9 May 2017


high-resolution terminology - matching measurements at high-resolution


Adenine nucleotides

Description

Adenine nucleotides, which are also sometimes referred to as adenosines or adenylates, are a group of organic molecules including AMP, ADP and ATP. These molecules present the major players of energy storage and transfer.

Abbreviation: AN






MitoPedia topics: Substrate and metabolite 

Adenine nucleotides and energy transfer

Adenine nucleotides have the typical structure of nucleotides including the purine base adenine attached to a five-carbon sugar and one to three phosphate groups. The three best known members of this family are the purine nucleotides AMP, ADP and ATP, which can be converted into each other by the addition or removal of one to two phosphate groups. This process stores or releases energy and is thereby essential for energy transfer and supply of multiple cellular reactions. The breaking of one phosphoanhydride bond releases 30.5 kJ/mol of energy. Thus, the dephosphorylation of the energy-rich ATP to ADP yields a free energy of 30.5 kJ/mol or even 61 kJ/mol when two phosphate groups are released (as shown below).

  • ATP + H2O β†’ ADP + Pi       Ξ”G = -30.5 kJ/mol
  • ADP + H2O β†’ AMP + Pi       Ξ”G = -30.5 kJ/mol
  • ATP + H2O β†’ AMP + 2Pi       Ξ”G = -61 kJ/mol

To restore the energy, an endergonic reaction, in which ATP is created from ADP and a free phosphate is needed. This reaction can be carried out by the membrane embedded ATP synthase (also called complex V). The energy which is used to generate ATP from ADP and Pi is hereby available in the form of hydrogen ions (H+), which are moved down an electrochemical gradient, e.g. from the intermembrane space into the mitochondrial matrix.

ATP and the free energy, which can be stored or generated by its conversion into ADP and AMP, is useful in many cellular processes, especially cellular respiration. It serves as an energy source for glycolysis, photosynthesis, fatty acid oxidation, anaerobic respiration, active transport mechanisms across the cell membrane - e.g. in the electron transfer system -, and synthesis of macromolecules such as DNA.

Nucleotides

Nucleotides are organic molecules and are made up of three subunits: a nitrogenous base (purine or pyrimidine base), a five-carbon sugar (ribose or deoxyribose) and one to three phosphate groups. With this, in short, nucleotides are nucleosides with attached phosphate group(s). Nucleotides present the building blocks of nucleic acids and by this form a part of essential biomolecules of life such as, for example, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). In addition, they make up components that play important roles in biochemical processes, namely nucleoside triphosphates (ATP, GTP, CTP and UTP), which can store and transfer energy (by the conversion of ATP to ADP), or cAMP and cGMP, which participate in cell signalling (cGMP and cAMP). Some nucleotides are also incorporated into important cofactors of enzymatic reactions, for example coenzyme A, FAD, FMN, NAD, and NADP+, and therefore serve essential cellular functions.