Adenosine monophosphate
Encyclopedia
Adenosine monophosphate (AMP), also known as 5'-adenylic acid, is a nucleotide
that is used as a monomer
in RNA
. It is an ester
of phosphoric acid
and the nucleoside adenosine. AMP consists of a phosphate
group, the sugar ribose
, and the nucleobase adenine
. As a substituent
it takes the form of the prefix adenylyl-.
synthesis by the enzyme adenylate kinase
by combining two ADP
molecules:
Or AMP may be produced by the hydrolysis
of one high energy phosphate
bond of ADP:
AMP can also be formed by hydrolysis of ATP
into AMP and pyrophosphate
:
When RNA is broken down by living systems, nucleoside monophosphates, including adenosine monophosphate, are formed.
AMP can be regenerated to ATP as follows:
AMP can be converted into IMP by the enzyme
myoadenylate deaminase, freeing an ammonia
group.
In a catabolic pathway, adenosine monophosphate can be converted to uric acid
, which is excreted from the body.
(or cAMP). Within certain cells the enzyme adenylate cyclase
makes cAMP from ATP, and typically this reaction is regulated by hormones such as adrenaline or glucagon
. cAMP plays an important role in intracellular signaling.
Nucleotide
Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA. In addition, nucleotides participate in cellular signaling , and are incorporated into important cofactors of enzymatic reactions...
that is used as a monomer
Monomer
A monomer is an atom or a small molecule that may bind chemically to other monomers to form a polymer; the term "monomeric protein" may also be used to describe one of the proteins making up a multiprotein complex...
in RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
. It is an ester
Ester
Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...
of phosphoric acid
Phosphoric acid
Phosphoric acid, also known as orthophosphoric acid or phosphoric acid, is a mineral acid having the chemical formula H3PO4. Orthophosphoric acid molecules can combine with themselves to form a variety of compounds which are also referred to as phosphoric acids, but in a more general way...
and the nucleoside adenosine. AMP consists of a phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
group, the sugar ribose
Ribose
Ribose is an organic compound with the formula C5H10O5; specifically, a monosaccharide with linear form H––4–H, which has all the hydroxyl groups on the same side in the Fischer projection....
, and the nucleobase adenine
Adenine
Adenine is a nucleobase with a variety of roles in biochemistry including cellular respiration, in the form of both the energy-rich adenosine triphosphate and the cofactors nicotinamide adenine dinucleotide and flavin adenine dinucleotide , and protein synthesis, as a chemical component of DNA...
. As a substituent
Substituent
In organic chemistry and biochemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon...
it takes the form of the prefix adenylyl-.
Production and degradation
AMP can be produced during ATPAdenosine triphosphate
Adenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism...
synthesis by the enzyme adenylate kinase
Adenylate kinase
Adenylate kinase is a phosphotransferase enzyme that catalyzes the interconversion of adenine nucleotides, and plays an important role in cellular energy homeostasis.-Substrate and products:...
by combining two ADP
Adenosine diphosphate
Adenosine diphosphate, abbreviated ADP, is a nucleoside diphosphate. It is an ester of pyrophosphoric acid with the nucleoside adenosine. ADP consists of the pyrophosphate group, the pentose sugar ribose, and the nucleobase adenine....
molecules:
- 2 ADP → ATP + AMP
Or AMP may be produced by the hydrolysis
Hydrolysis
Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization...
of one high energy phosphate
High energy phosphate
High-energy phosphate can mean one of two things:* The phosphate-phosphate bonds formed when compounds such as adenosine diphosphate and adenosine triphosphate are created....
bond of ADP:
- ADP → AMP + PiPhosphateA phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
AMP can also be formed by hydrolysis of ATP
Adenosine triphosphate
Adenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism...
into AMP and pyrophosphate
Pyrophosphate
In chemistry, the anion, the salts, and the esters of pyrophosphoric acid are called pyrophosphates. Any salt or ester containing two phosphate groups is called a diphosphate. As a food additive, diphosphates are known as E450.- Chemistry :...
:
- ATP → AMP + PPiPyrophosphateIn chemistry, the anion, the salts, and the esters of pyrophosphoric acid are called pyrophosphates. Any salt or ester containing two phosphate groups is called a diphosphate. As a food additive, diphosphates are known as E450.- Chemistry :...
When RNA is broken down by living systems, nucleoside monophosphates, including adenosine monophosphate, are formed.
AMP can be regenerated to ATP as follows:
- AMP + ATP → 2 ADP (adenylate kinase in the opposite direction)
- ADP + Pi → ATP (this step is most often performed in aerobes by the ATP synthaseATP synthaseright|thumb|300px|Molecular model of ATP synthase by X-ray diffraction methodATP synthase is an important enzyme that provides energy for the cell to use through the synthesis of adenosine triphosphate . ATP is the most commonly used "energy currency" of cells from most organisms...
during oxidative phosphorylationOxidative phosphorylationOxidative phosphorylation is a metabolic pathway that uses energy released by the oxidation of nutrients to produce adenosine triphosphate . Although the many forms of life on earth use a range of different nutrients, almost all aerobic organisms carry out oxidative phosphorylation to produce ATP,...
)
AMP can be converted into IMP by the enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
myoadenylate deaminase, freeing an ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
group.
In a catabolic pathway, adenosine monophosphate can be converted to uric acid
Uric acid
Uric acid is a heterocyclic compound of carbon, nitrogen, oxygen, and hydrogen with the formula C5H4N4O3. It forms ions and salts known as urates and acid urates such as ammonium acid urate. Uric acid is created when the body breaks down purine nucleotides. High blood concentrations of uric acid...
, which is excreted from the body.
cAMP
AMP can also exist as a cyclic structure known as cyclic AMPCyclic adenosine monophosphate
Cyclic adenosine monophosphate is a second messenger important in many biological processes...
(or cAMP). Within certain cells the enzyme adenylate cyclase
Adenylate cyclase
Adenylate cyclase is part of the G protein signalling cascade, which transmits chemical signals from outside the cell across the membrane to the inside of the cell ....
makes cAMP from ATP, and typically this reaction is regulated by hormones such as adrenaline or glucagon
Glucagon
Glucagon, a hormone secreted by the pancreas, raises blood glucose levels. Its effect is opposite that of insulin, which lowers blood glucose levels. The pancreas releases glucagon when blood sugar levels fall too low. Glucagon causes the liver to convert stored glycogen into glucose, which is...
. cAMP plays an important role in intracellular signaling.