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Ribose is a
simple sugar Monosaccharides (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is app ...
and
carbohydrate is a disaccharide A disaccharide (also called a double sugar or ''biose'') is the sugar formed when two monosaccharides are joined by glycosidic linkage. Like monosaccharides, disaccharides are simple sugars soluble in water. Three common ex ...
with
molecular formula A chemical formula is a way of presenting information about the chemical proportions of atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and takes ...
C5H10O5 and the linear-form composition H−(C=O)−(CHOH)4−H. The naturally-occurring form, , is a component of the
ribonucleotideIn biochemistry, a ribonucleotide is a nucleotide Nucleotides are organic molecules , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen chemical bond, ...
s from which
RNA Ribonucleic acid (RNA) is a polymer A polymer (; Greek ''wikt:poly-, poly-'', "many" + ''wikt:-mer, -mer'', "part") is a Chemical substance, substance or material consisting of very large molecules, or macromolecules, composed of many Re ...

RNA
is built, and so this compound is necessary for
coding Coding may refer to: Computer science * Computer programming, the process of creating and maintaining the source code of computer programs * Line coding, in data storage * Source coding, compression used in data transmission * Coding theory * Chann ...

coding
,
decoding
decoding
,
regulation Regulation is the management of complex systems A complex system is a system composed of many components which may interaction, interact with each other. Examples of complex systems are Earth's global climate, organisms, the human brain, infras ...
and
expression
expression
of
gene In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molecular interactions, Physiology, physiological mecha ...

gene
s. It has a
structural analog A structural analog (analogue in Commonwealth English The use of the English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon England, early medieval England, which has eventua ...
,
deoxyribose Deoxyribose, or more precisely 2-deoxyribose, is a monosaccharide Monosaccharides (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Rep ...

deoxyribose
, which is a similarly essential component of
DNA Deoxyribonucleic acid (; DNA) is a molecule File:Pentacene on Ni(111) STM.jpg, A scanning tunneling microscopy image of pentacene molecules, which consist of linear chains of five carbon rings. A molecule is an electrically neutral gro ...

DNA
. is an unnatural sugar that was first prepared by
Emil Fischer Hermann Emil Louis Fischer FRS FRSE FCS (c; ; 9 October 185215 July 1919) was a German chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist A scientist is a person ...
and
Oscar Piloty Oskar Piloty (30 April 1866 – 6 October 1915) was a German chemist. Life Oskar Piloty was born the son of the painter Karl von Piloty Karl Theodor von Piloty (1 October 1826 – 21 July 1886) was a Germany, German Painting, painter, noted fo ...
in 1891. It was not until 1909 that
Phoebus Levene Phoebus Aaron Theodore Levene (25 February 1869 – 6 September 1940) was an American biochemist Biochemists are scientists who are trained in biochemistry Biochemistry or biological chemistry, is the study of chemical process In a scien ...
and Walter Jacobs recognised that was a
natural product A natural product is a chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entity, molecular entities) composed of atoms from more than one chemical element, element held together b ...
, the
enantiomer In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they und ...

enantiomer
of Fischer and Piloty's product, and an essential component of
nucleic acid Nucleic acids are biopolymers, macromolecules, essential to all Organism, known forms of life. They are composed of nucleotides, which are the monomers made of three components: a pentose, 5-carbon sugar, a phosphate group and a nitrogenous base. ...

nucleic acid
s. Fischer chose the name "ribose" as it is a partial rearrangement of the name of another sugar,
arabinose Arabinose is an aldopentose – a monosaccharide Monosaccharides (from Greek '' monos'': single, ''sacchar'': sugar), also called simple sugars, are the simplest form of sugar Sugar is the generic name for Sweetness, sweet-tasting, soluble ...

arabinose
, of which ribose is an
epimer In stereochemistry s. Stereochemistry focuses on stereoisomer In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but diff ...
at the 2' carbon; both names also relate to
gum arabic '', pictured in a medicinal handbook: Franz Eugen Köhler, ''Köhler's Medizinal-Pflanzen'' (1887) Gum arabic, also known as ''gum sudani'', acacia gum, Arabic gum, gum acacia, acacia, Senegal gum, ''Indian gum'', and by other names, is a natur ...
, from which arabinose was first isolated and from which they prepared . Like most sugars, ribose exists as a mixture of cyclic forms in
equilibrium List of types of equilibrium, the condition of a system in which all competing influences are balanced, in a wide variety of contexts. Equilibrium may also refer to: Film and television * Equilibrium (film), ''Equilibrium'' (film), a 2002 scien ...
with its linear form, and these readily interconvert especially in
aqueous solution An aqueous solution is a solution Solution may refer to: * Solution (chemistry) Image:SaltInWaterSolutionLiquid.jpg, upMaking a saline water solution by dissolving Salt, table salt (sodium chloride, NaCl) in water. The salt is the solute an ...
. The name "ribose" is used in biochemistry and biology to refer to all of these forms, though more specific names for each are used when required. In its linear form, ribose can be recognised as the
pentose In , a pentose is a (simple sugar) with five . The of all pentoses is , and their is 150.13 g/mol.-Ri ...

pentose
sugar with all of its
hydroxyl A hydroxy or hydroxyl group is a functional group with the chemical formula -OH and composed of one oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the ...

hydroxyl
functional group In organic chemistry, a functional group is a substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions re ...
s on the same side in its
Fischer projection The Fischer projection, devised by Emil Fischer in 1891, is a two-dimensional representation of a Three-dimensional space, three-dimensional organic molecule by Graphical projection, projection. Fischer projections were originally proposed for the ...

Fischer projection
. has these hydroxyl groups on the right hand side and is associated with the
systematic nameA systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance A chemical substance is a form of matter In classical physics and general chemistry, matter is any substance that has mass and ...
(2''R'',3''R'',4''R'')-2,3,4,5-tetrahydroxypentanal, whilst has its hydroxyl groups appear on the left hand side in a Fischer projection. Cyclisation of ribose occurs via
hemiacetal A hemiacetal or a hemiketal have the general formula R1R2C(OH)OR, where R1 or R2 is hydrogen or an organic substituent. They generally result from the addition of an alcohol In , alcohol is an that carries at least one (−OH) bound to a ...

hemiacetal
formation due to attack on the
aldehyde Chemically, an aldehyde is a compound containing a functional group In organic chemistry, a functional group is a substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same fu ...

aldehyde
by the C4' hydroxyl group to produce a
furanose A furanose is a collective term for carbohydrates is a disaccharide found in animal milk. It consists of a molecule of galactose, D-galactose and a molecule of glucose, D-glucose bonded by beta-1-4 glycosidic linkage. A carbohydrate () is a bio ...
form or by the C5' hydroxyl group to produce a
pyranosePyranose is a collective term for saccharides that have a chemical structure that includes a six-membered ring consisting of five carbon atoms and one oxygen atom. There may be other carbons external to the ring. The name derives from its similarity ...
form. In each case, there are two possible geometric outcomes, named as α- and β- and known as
anomer An anomer is a type of geometric variation found at certain atoms in carbohydrate is a disaccharide found in animal milk. It consists of a molecule of D-galactose and a molecule of D-glucose bonded by beta-1-4 glycosidic linkage. A carboh ...
s, depending on the
stereochemistry s. Stereochemistry focuses on stereoisomer In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dim ...

stereochemistry
at the hemiacetal carbon atom (the "anomeric carbon"). At room temperature, about 76% of is present in pyranose forms (α:β = 1:2) and 24% in the furanose forms (α:β = 1:3), with only about 0.1% of the linear form present. The
ribonucleosideA ribonucleoside is a type of nucleoside including ribose as a component. An example is cytidine. References

{{Chem-stub Nucleosides, * Ribosides ...
s
adenosine Adenosine is an organic compound , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen chemical bond, bonds. Due to carbon's ability to Catenation, cate ...

adenosine
,
cytidine Cytidine (symbol A symbol is a mark, sign, or that indicates, signifies, or is understood as representing an , , or . Symbols allow people to go beyond what is n or seen by creating linkages between otherwise very different s and s. All ( ...

cytidine
,
guanosine Guanosine (symbol A symbol is a mark, sign, or word In linguistics, a word of a spoken language can be defined as the smallest sequence of phonemes that can be uttered in isolation with semantic, objective or pragmatics, practical meaning ( ...
, and
uridine Uridine (nucleoside#List of nucleosides and corresponding nucleobases, symbol U or Urd) is a glycosylated pyrimidine analog containing uracil attached to a ribose ring (or more specifically, a ribofuranose) via a β-N1-glycosidic bond. It is one o ...
are all
derivative In mathematics Mathematics (from Greek: ) includes the study of such topics as numbers (arithmetic and number theory), formulas and related structures (algebra), shapes and spaces in which they are contained (geometry), and quantities ...
s of β--ribofuranose. species that include
phosphorylated In chemistry, phosphorylation of a molecule is the attachment of a phosphoryl group. This process and its inverse, dephosphorylation, are critical for many cellular processes in biology. Protein phosphorylation is especially important for their fu ...
ribose include ,
ATP ATP may refer to: Companies and organizations * Association of Tennis Professionals * American Technical Publishers * ', a Danish pension * Armenia Tree Project * Association for Transpersonal Psychology * ATP architects engineers office * ATP ...

ATP
,
coenzyme A Coenzyme A (CoA, SHCoA, CoASH) is a coenzyme, notable for its role in the Fatty acid metabolism#Synthesis, synthesis and Fatty acid metabolism#.CE.B2-Oxidation, oxidation of fatty acids, and the oxidation of pyruvic acid, pyruvate in the citric aci ...
, and
NADH Nicotinamide adenine dinucleotide (NAD) is a Cofactor (biochemistry), coenzyme central to metabolism. Found in all living cell (biology), cells, NAD is called a dinucleotide because it consists of two nucleotides joined through their phosphate ...
.
cAMP Camp may refer to: Outdoor accommodation and recreation * Campsite or campground, a recreational outdoor sleeping and eating site * a temporary settlement for nomads * Camp, a term used in New England, Northern Ontario and New Brunswick to describ ...
and cGMP serve as secondary messengers in some signaling pathways and are also ribose derivatives. The ribose
moiety Moiety may refer to: * Moiety (chemistry), a part or functional group of a molecule * Moiety (kinship), either of two groups into which a society is divided * A division of society in the Iroquois government and societal structure * An Australian Ab ...
appears in some pharmaceutical agents, including the antibiotics
neomycin Neomycin is an aminoglycoside antibiotic that displays bactericidal activity against gram-negative aerobic bacilli and some anaerobic bacilli where resistance has not yet arisen. It is generally not effective against gram-positive bacilli and anae ...

neomycin
and
paromomycin Paromomycin is an antimicrobial An antimicrobial is an agent that kills microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism In biology, an organism () is any organic, life, living system that functions ...

paromomycin
.


Synthesis and sources

Ribose as its 5-phosphate ester is typically produced from glucose by the
pentose phosphate pathway In chemistry, a pentose is a monosaccharide (simple sugar) with five carbon atom, atoms. The chemical formula of all pentoses is , and their molecular weight is 150.13 g/mol.
. In at least some archaea, alternative pathways have been identified. Ribose can be synthesized chemically, but commercial production relies on fermentation of glucose. Using genetically modified strains of ''B. subtilis'', 90 g/liter of ribose can be produced from 200 g of glucose. The conversion entails the intermediacy of gluconate and ribulose. Ribose has been detected in
meteorite A meteorite is a solid piece of debris from an object, such as a comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces ...
s.


Structure

Ribose is an
aldopentoseIn chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo ...

aldopentose
(a monosaccharide containing five
carbon Carbon (from la, carbo "coal") is a with the C and 6. It is lic and —making four s available to form s. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust. Three occur naturally, ...

carbon
atoms) that, in its
open chainIn chemistry, an open-chain compound (also spelled as open chain compound) or acyclic compound (Greek prefix "α", ''without'' and "κύκλος", ''cycle'') is a compound with a linear structure, rather than a Cyclic compound, cyclic one. An open-ch ...
form, has an
aldehyde Chemically, an aldehyde is a compound containing a functional group In organic chemistry, a functional group is a substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same fu ...

aldehyde
functional group In organic chemistry, a functional group is a substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions re ...
at one end. In the conventional numbering scheme for monosaccharides, the carbon atoms are numbered from C1' (in the aldehyde group) to C5'. The
deoxyribose Deoxyribose, or more precisely 2-deoxyribose, is a monosaccharide Monosaccharides (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Rep ...

deoxyribose
derivative found in DNA differs from ribose by having a
hydrogen Hydrogen is the chemical element with the Symbol (chemistry), symbol H and atomic number 1. Hydrogen is the lightest element. At standard temperature and pressure, standard conditions hydrogen is a gas of diatomic molecules having the che ...

hydrogen
atom in place of the
hydroxyl A hydroxy or hydroxyl group is a functional group with the chemical formula -OH and composed of one oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the ...

hydroxyl
group at C2'. This hydroxyl group performs a function in
RNA splicing RNA splicing is a process in molecular biology where a newly-made precursor messenger RNA (pre-mRNA) transcription (biology), transcript is transformed into a mature messenger RNA (Messenger RNA, mRNA). It works by removing introns (non-coding re ...

RNA splicing
. The "-" in the name -ribose refers to the
stereochemistry s. Stereochemistry focuses on stereoisomer In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dim ...

stereochemistry
of the
chiral Chirality is a property of important in several branches of science. The word ''chirality'' is derived from the (''kheir''), "hand", a familiar chiral object. An object or a system is ''chiral'' if it is distinguishable from its ; that is, i ...
carbon atom farthest away from the aldehyde group (C4'). In -ribose, as in all -sugars, this carbon atom has the same configuration as in -glyceraldehyde. File:Alpha-D-Ribopyranose numbered.png, α--Ribopyranose File:Beta-D-Ribopyranose numbered.png, β--Ribopyranose File:Alpha-D-Ribofuranose numbered.png, α--Ribofuranose File:Beta-D-Ribofuranose Numbered.png, β--Ribofuranose Relative abundance of forms of ribose in solution: β--ribopyranose (59%), α--ribopyranose (20%), β--ribofuranose (13%), α--ribofuranose (7%) and open chain (0.1%). For ribose residues in
nucleoside Nucleosides are s that can be thought of as s without a . A nucleoside consists simply of a (also termed a nitrogenous base) and a five-carbon sugar ( or 2'-deoxyribose) whereas a nucleotide is composed of a nucleobase, a five-carbon sugar, and ...

nucleoside
s and
nucleotide Nucleotides are organic molecules , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen chemical bond, bonds. Due to carbon's ability to Catenation, ...

nucleotide
, the torsion angles for the rotation encompassing the bonds influence the configuration of the respective nucleoside and nucleotide. The
secondary structure Biomolecular structure is the intricate folded, three-dimensional shape that is formed by a molecule A scanning tunneling microscopy image of pentacene molecules, which consist of linear chains of five carbon rings. A molecule is an elect ...

secondary structure
of a nucleic acid is determined by the rotation of its 7
torsion angle Torsion may refer to: Mathematics * Torsion of a curve * Torsion tensor in differential geometry * Torsion (algebra) * Torsion group In group theory The popular puzzle Rubik's cube invented in 1974 by Ernő Rubik has been used as an ill ...
s. Having a large amount of torsion angles allows for greater flexibility. In closed ring riboses, the observed flexibility mentioned above is not observed because the ring cycle imposes a limit on the number of torsion angles possible in the structure. Conformers of closed form riboses differ in regards to how the lone
oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

oxygen
in the molecule is positioned respective to the
nitrogenous base Nucleobases, also known as ''nitrogenous bases'' or often simply ''bases'', are nitrogen-containing biological compounds that form nucleosides Nucleosides are glycosylamines that can be thought of as nucleotide Nucleotides are organic mo ...
(also known as a
nucleobase 230px, Pyrimidine nucleobases are simple ring molecules. Nucleobases, also known as ''nitrogenous bases'' or often simply ''bases'', are nitrogen-containing biological compounds that form nucleosides Nucleosides are glycosylamines that can be ...
or just a base) attached to the ribose. If a carbon is facing towards the base, then the ribose is labeled as endo. If a carbon is facing away from the base, then the ribose is labeled as exo. If there is an oxygen molecule attached to the 2' carbon of a closed cycle ribose, then the exo confirmation is more stable because it decreases the interactions of the oxygen with the base. The difference itself is quite small, but when looking at an entire chain of RNA the slight difference amounts to a sizable impact. File:2' endo.jpg, 2' endo File:2' endo 3' exo.jpg, 2' endo 3' exo File:3' endo 2' exo.jpg, 3' endo 2' exo File:3' endo.jpg, 3' endo A ribose molecule is typically represented as a planar molecule on paper. Despite this, it is typically non-planar in nature. Even between hydrogen atoms, the many constituents on a ribose molecule cause
steric hindrance Steric effects are nonbonding interactions that influence the shape (conformational isomerism, conformation) and chemical reaction, reactivity of ions and molecules. Steric effects complement electronic effects, which dictate the shape and reactiv ...
and strain between them. To relieve this crowding and
ring strainIn organic chemistry, ring strain is a type of instability that exists when bonds in a molecule form angles that are abnormal. Strain is most commonly discussed for small rings such as cyclopropanes and cyclobutanes, whose internal angles are subs ...
, the ring puckers, i.e. becomes non-planar. This puckering is achieved by displacing an atom from the plane, relieving the strain and yielding a more stable configuration. Puckering, otherwise known as the sugar ring conformation (specifically ribose sugar), can be described by the amplitude of pucker as well as the
pseudorotation A pseudorotation is a set of intramolecular movements of attached groups (i.e., ligand In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding ...
angle. The pseudo-rotation angle can be described as either "north (N)" or "south (S)" range. While both ranges are found in double helices, the north range is commonly associated with RNA and the A form of DNA. In contrast, the south range is associated with B form DNA.
Z-DNA Z-DNA is one of the many possible double helical structures of DNA. It is a left-handed double helical structure in which the helix winds to the left in a zigzag pattern, instead of to the right, like the more common B-DNA In molecular biolog ...
contains sugars in both the north and south ranges. When only a single atom is displaced, it is referred to as an "envelope" pucker. When two atoms are displaced, it is referred to as a "twist" pucker, in reference to the zigzag orientation. In an "endo" pucker, the major displacement of atoms is on the β-face, the same side as the C4'-C5' bond and the base. In an "exo" pucker, the major displacement of atoms is on the α-face, on the opposite side of the ring. The major forms of ribose are the 3'-endo pucker (commonly adopted by RNA and A-form DNA) and 2'-endo pucker (commonly adopted by B-form DNA). These ring puckers are developed from changes in ring torsion angles; there are infinite combinations of angles so therefore, there is an infinite number of transposable pucker conformations, each separated by disparate activation energies.


Functions

ATP is derived from ribose; it contains one ribose, three
phosphate In chemistry, a phosphate is an anion, salt (chemistry), salt, functional group or ester derived from a phosphoric acids and phosphates, phosphoric acid. It most commonly means orthophosphate, a derivative of phosphoric acid, orthophosphoric a ...

phosphate
groups, and an
adenine Adenine (A, Ade) is a nucleobase 230px, Pyrimidine nucleobases are simple ring molecules. Nucleobases, also known as ''nitrogenous bases'' or often simply ''bases'', are nitrogen-containing biological compounds that form nucleosides Nucleos ...

adenine
base. ATP is created during
cellular respiration Cellular respiration is a set of metabolic Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life Life is a characteristic that distinguishes physical entities that have biological processes, such a ...

cellular respiration
from
adenosine diphosphate Adenosine diphosphate (ADP), also known as adenosine pyrophosphate (APP), is an important organic compound In , organic compounds are generally any s that contain - . Due to carbon's ability to (form chains with other carbon s), millions of o ...

adenosine diphosphate
(ATP with one less phosphate group).


Signaling pathways

Ribose is a building block in secondary signaling molecules such as
cyclic adenosine monophosphate Cyclic adenosine monophosphate (cAMP, cyclic AMP, or 3',5'-cyclic adenosine monophosphate Adenosine is an organic compound In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make u ...
(cAMP) which is derived from ATP. One specific case in which cAMP is used is in cAMP-dependent signaling pathways. In cAMP signaling pathways, either a stimulative or inhibitory hormone receptor is activated by a
signal molecule In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molecular interactions, Physiology, physiological mechanisms ...
. These receptors are linked to a stimulative or inhibitory regulative
G-protein G proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switch A scanning tunneling microscopy image of pentacene molecules, which consist of linear chains of five carbon rings. A ...
. When a stimulative G-protein is activated,
adenylyl cyclase Adenylyl cyclase (, also commonly known as adenyl cyclase and adenylate cyclase, abbreviated AC) is an enzyme with key regulatory roles in essentially all Cell (biology), cells. It is the most Polyphyly, polyphyletic known enzyme: six distinct cla ...

adenylyl cyclase
catalyzes that utilizes a low-temperature oxidation catalyst to convert carbon monoxide to less toxic carbon dioxide Carbon dioxide (chemical formula ) is a colorless gas with a density about 53% higher than that of dry air. Carbon dioxide molecules ...

catalyzes
ATP into cAMP by using Mg2+ or Mn2+. cAMP, a secondary messenger, then goes on to activate
protein kinase A In cell biology Cell biology (also cellular biology or cytology) is a branch of biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, ...
, which is an
enzyme Enzymes () are proteins that act as biological catalysts (biocatalysts). Catalysts accelerate chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates in ...

enzyme
that regulates cell
metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life Life is a characteristic that distinguishes physical entities A bubble of exhaled gas in water In common usage and classical mechanics, a phys ...

metabolism
. Protein kinase A regulates metabolic enzymes by
phosphorylation In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, properties, behavior and the changes they undergo during ...

phosphorylation
which causes a change in the cell depending on the original signal molecule. The opposite occurs when an inhibitory G-protein is activated; the G-protein inhibits adenylyl cyclase and ATP is not converted to cAMP.


Metabolism

Ribose is referred to as the "molecular currency" because of its involvement in intracellular energy transfers. For example,
nicotinamide adenine dinucleotide Nicotinamide adenine dinucleotide (NAD) is a coenzyme A cofactor is a non-protein Proteins are large biomolecules or macromolecules that are comprised of one or more long chains of amino acid residue (biochemistry), residues. Proteins p ...
(NAD),
flavin adenine dinucleotide In biochemistry Biochemistry or biological chemistry, is the study of chemical process In a scientific Science () is a systematic enterprise that Scientific method, builds and organizes knowledge in the form of Testability, testable ...

flavin adenine dinucleotide
(FAD), and
nicotinamide adenine dinucleotide phosphate Nicotinamide adenine dinucleotide phosphate, abbreviated NADP or, in older notation, TPN (triphosphopyridine nucleotide), is a cofactor used in anabolic reactions, such as the Calvin cycle The Calvin cycle, light-independent reactions, bio sy ...
(NADP) all contain the -ribofuranose
moiety Moiety may refer to: * Moiety (chemistry), a part or functional group of a molecule * Moiety (kinship), either of two groups into which a society is divided * A division of society in the Iroquois government and societal structure * An Australian Ab ...
. They can each be derived from -ribose after it is converted to by the enzyme ribokinase. NAD, FAD, and NADP act as electron acceptors in biochemical
redox Redox (reduction–oxidation, pronunciation: or ) is a type of chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substance A chemical substance is a form of matter ...

redox
reactions in major metabolic pathways including
glycolysis Glycolysis is the metabolic pathway In biochemistry, a metabolic pathway is a linked series of chemical reaction A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of on ...

glycolysis
, the
citric acid cycle The citric acid cycle (CAC) – also known as the TCA cycle (tricarboxylic acid cycle) or the Krebs cycle – is a series of chemical reactions to release stored energy through the redox, oxidation of acetyl-CoA derived from carbohydra ...

citric acid cycle
,
fermentation Fermentation is a metabolic Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life Life is a characteristic that distinguishes physical entities that have biological processes, such as Cell signalin ...

fermentation
, and the
electron transport chain An electron transport chain (ETC) is a series of protein complex A protein complex or multiprotein complex is a group of two or more associated polypeptide chain Peptides (from Greek language Greek (modern , romanized: ''Elliniká'', Anc ...

electron transport chain
.


Nucleotide biosynthesis

Nucleotides are synthesized through salvage or
de novo synthesis ''De novo'' synthesis refers to the synthesis of complex molecules from simple molecules such as sugar Sugar is the generic name for , soluble s, many of which are used in food. Simple sugars, also called s, include , , and . Compound suga ...
.
Nucleotide salvageA salvage pathway is a Metabolic pathway, pathway in which a biological product is produced from intermediates in the degradative pathway of its own or a similar substance. The term often refers to nucleotide salvage in particular, in which nucleotid ...
uses pieces of previously made nucleotides and re-synthesizes them for future use. In de novo, amino acids, carbon dioxide, folate derivatives, and
phosphoribosyl pyrophosphate Phosphoribosyl pyrophosphate (PRPP) is a pentosephosphate. It is formed from ribose 5-phosphate by the enzyme ribose-phosphate diphosphokinase. It plays a role in transferring phospho-ribose groups in several reactions: In ''de novo In ge ...

phosphoribosyl pyrophosphate
(PRPP) are used to synthesize nucleotides. Both de novo and salvage require PRPP which is synthesized from ATP and ribose 5-phosphate by an enzyme called PRPP synthetase.


Modifications


Modifications in nature

Ribokinase catalyzes the conversion of -ribose to . Once converted, -ribose-5-phosphate is available for the manufacturing of the
amino acids Amino acids are organic compound In , organic compounds are generally any s that contain - . Due to carbon's ability to (form chains with other carbon s), millions of organic compounds are known. The study of the properties, reactions, a ...

amino acids
tryptophan Tryptophan (symbol Trp or W) is an α-amino acid that is used in the biosynthesis of proteins. Tryptophan contains an α-amino group, an α-carboxylic acid group, and a side chain indole, making it a non-polar Aromatic hydrocarbon, aromatic amino ...

tryptophan
and
histidine Histidine (symbol His or H) is an α-amino acid Amino acids are organic compound , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen chemical bon ...

histidine
, or for use in the
pentose phosphate pathway In chemistry, a pentose is a monosaccharide (simple sugar) with five carbon atom, atoms. The chemical formula of all pentoses is , and their molecular weight is 150.13 g/mol.
. The absorption of -ribose is 88–100% in the small intestines (up to 200 mg/kg·h). One important modification occurs at the C2' position of the ribose molecule. By adding an group, the nuclear resistance of the RNA is increased because of additional stabilizing forces. These forces are stabilizing because of the increase of intramolecular hydrogen bonding and an increase in the
glycosidic bond A glycosidic bond or glycosidic linkage is a type of covalent bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate. A glycosidic bond is formed between the hemiacetal or hemiketal group ...
stability. The resulting increase of resistance leads to increases in the
half-life Half-life (symbol ''t''1⁄2) is the time required for a quantity to reduce to half of its initial value. The term is commonly used in nuclear physics Nuclear physics is the field of physics Physics is the natural science that studies ...
of
siRNA Small interfering RNA (siRNA), sometimes known as short interfering RNA or silencing RNA, is a class of double-stranded RNA non-coding RNA molecules, typically 20-24 base pairs in length, similar to MicroRNA, miRNA, and operating within the RNA i ...
and the potential therapeutic potential in cells and animals. The
methylation In the chemical sciences, methylation denotes the addition of a methyl group A methyl group is an alkyl derived from methane, containing one carbon atom chemical bond, bonded to three hydrogen atoms — CH3. In chemical formula, fo ...

methylation
of ribose at particular sites is correlated with a decrease in immune stimulation.


Synthetic modifications

Along with phosphorylation, ribofuranose molecules can exchange their oxygen with
selenium Selenium is a chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that ...

selenium
and
sulfur Sulfur (in nontechnical British English: sulphur) is a chemical element In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: th ...

sulfur
to produce similar sugars that only vary at the 4' position. These derivatives are more
lipophilic Lipophilicity (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is approxi ...
than the original molecule. Increased lipophilicity makes these species more suitable for use in techniques such as
PCR Polymerase chain reaction (PCR) is a method widely used to rapidly make millions to billions of copies (complete copies or partial copies) of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it (or a pa ...

PCR
, RNA aptamer post-modification, antisense technology, and for phasing data. Similar to the 2' modifications in nature, a synthetic modification of ribose includes the addition of
fluorine Fluorine is a chemical element with the Chemical symbol, symbol F and atomic number 9. It is the lightest halogen and exists at Standard conditions for temperature and pressure, standard conditions as a highly toxic, pale yellow Diatomic molecule ...

fluorine
at the 2' position. This
fluorinated In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, properties, behavior and the changes they undergo during ...
ribose acts similar to the methylated ribose because it is capable of suppressing immune stimulation depending on the location of the ribose in the DNA strand. The big difference between methylation and fluorination, is the latter only occurs through synthetic modifications. The addition of Fluorine leads to an increase in the stabilization of the glycosidic bond and an increase of intramolecular hydrogen bonds.


Medical uses

-ribose has been suggested for use in management of
congestive heart failure Heart failure (HF), also known as congestive heart failure (CHF) and (congestive) cardiac failure (CCF), is a set of manifestations caused by the failure of the heart The heart is a cardiac muscle, muscular Organ (biology), organ in mos ...
(as well as other forms of heart disease) and for
chronic fatigue syndrome Chronic fatigue syndrome (CFS), also called myalgic encephalomyelitis (ME) and ME/CFS, is a complex, fatiguing, long-term medical condition diagnosed by required primary symptoms and criteria, and often involves a broad range of symptoms. Disting ...
(CFS), also called myalgic encephalomyelitis (ME) in an open-label non-blinded, non-randomized, and non-crossover subjective study. Supplemental -ribose can bypass part of the
pentose phosphate pathway In chemistry, a pentose is a monosaccharide (simple sugar) with five carbon atom, atoms. The chemical formula of all pentoses is , and their molecular weight is 150.13 g/mol.
, an energy-producing pathway, to produce -ribose-5-phosphate. The enzyme glucose-6-phosphate-dehydrogenase (G-6-PDH) is often in short supply in cells, but more so in diseased tissue, such as in
myocardial Cardiac muscle (also called heart muscle or myocardium) is one of three types of vertebrate Vertebrates () comprise all species of animal Animals (also called Metazoa) are multicellular eukaryotic organisms that form the Kingdom (biolo ...

myocardial
cells in patients with cardiac disease. The supply of -ribose in the
mitochondria A mitochondrion (; ) is a double-membrane A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Biological membranes include cell membranes ...

mitochondria
is directly correlated with ATP production; decreased -ribose supply reduces the amount of ATP being produced. Studies suggest that supplementing -ribose following tissue ischemia (e.g. myocardial ischemia) increases myocardial ATP production, and therefore mitochondrial function. Essentially, administering supplemental -ribose bypasses an enzymatic step in the pentose phosphate pathway by providing an alternate source of 5-phospho--ribose 1-
pyrophosphate In chemistry, pyrophosphates are phosphorus oxyanions that contain two phosphorus atoms in a P–O–P linkage. A number of pyrophosphate salts exist, such as disodium pyrophosphate (Na2H2P2O7) and tetrasodium pyrophosphate (Na4P2O7), among others ...
for ATP production. Supplemental -ribose enhances recovery of ATP levels while also reducing cellular injury in humans and other animals. One study suggested that the use of supplemental -ribose reduces the instance of
angina Angina, also known as angina pectoris, is chest pain Chest pain is pain or discomfort in the chest, typically the front of the chest. It may be described as sharp, dull, pressure, heaviness or squeezing. Associated symptoms may include pain in ...

angina
in men with diagnosed
coronary artery disease Coronary artery disease (CAD), also called coronary heart disease (CHD), ischemic heart disease (IHD), or simply heart disease, involves the reduction of blood flow to the heart muscle Cardiac muscle (also called heart muscle or myocardium) i ...
. -Ribose has been used to treat many
pathological Pathology is the study of the causesCauses, or causality, is the relationship between one event and another. It may also refer to: * Causes (band), an indie band based in the Netherlands * Causes (company), an online company See also * Cau ...
conditions, such as chronic fatigue syndrome,
fibromyalgia Fibromyalgia (FM) is a medical condition characterized by chronic widespread pain Pain is a distressing feeling often caused by intense or damaging stimuli. The defines pain as "an unpleasant sensory and emotional experience associated wi ...

fibromyalgia
, and myocardial dysfunction. It is also used to reduce symptoms of cramping, pain, stiffness, etc. after exercise and to improve athletic performance.


References

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