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Purine is a
heterocyclic A heterocyclic compound or ring structure is a cyclic compound A cyclic compound (''ring compound'') is a term for a compound in the field of chemistry Chemistry is the scientific discipline involved with Chemical element, elements and c ...
aromatic In chemistry Chemistry is the scientific Science () is a systematic enterprise that builds and organizes knowledge Knowledge is a familiarity or awareness, of someone or something, such as facts A fact is an occurrence in ...

aromatic
organic compound 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 ...
that consists of two rings (
pyrimidine Pyrimidine is an aromatic In chemistry Chemistry is the scientific Science () is a systematic enterprise that builds and organizes knowledge Knowledge is a familiarity or awareness, of someone or something, such as facts ...

pyrimidine
and
imidazole Imidazole is an organic compound 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 ...
) fused together. It is
water Water (chemical formula H2O) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known li ...

water
-soluble. Purine also gives its name to the wider class of
molecule A molecule is an electrically Electricity is the set of physical phenomena associated with the presence and motion Image:Leaving Yongsan Station.jpg, 300px, Motion involves a change in position In physics, motion is the phenomenon ...

molecule
s, purines, which include substituted purines and their
tautomer Tautomers () are structural isomer In chemistry, a structural isomer (or constitutional isomer in the IUPAC nomenclature) of a chemical compound, compound is another compound whose molecule has the same number of atoms of each element, but with ...

tautomer
s. They are the most widely occurring
nitrogen Nitrogen is the 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 ...

nitrogen
-containing heterocycles in nature.


Dietary sources

Purines are found in high concentration in meat and meat products, especially internal organs such as
liver The liver is an organ Organ may refer to: Biology * Organ (anatomy) An organ is a group of Tissue (biology), tissues with similar functions. Plant life and animal life rely on many organs that co-exist in organ systems. A given organ's t ...

liver
and
kidney The kidneys are two reddish-brown bean-shaped organs An organ is a group of tissues with similar functions. Plant life and animal life rely on many organs that co-exist in organ systems. A given organ's tissues can be broadly categorized ...

kidney
. In general, plant-based diets are low in purines. Examples of high-purine sources include:
sweetbread Sweetbread is a culinary name for the thymus (also called throat, gullet, or neck sweetbread) or pancreas (also called stomach, belly or gut sweetbread), typically from calf (''ris de veau'') and lamb and mutton, lamb (''ris d'agneau''). The "he ...
s,
anchovies An anchovy is a small, common forage fish Forage fish, also called prey fish or bait fish, are small pelagic fish which are preyed on by larger predators for food. Predators include other larger fish, seabirds and marine mammals. Typical oce ...
,
sardines "Sardine" and "pilchard" are common names that refer to various small, Oily fish, oily forage fish in the herring family Clupeidae. The term "sardine" was first used in English during the early 15th century and may come from the Mediterranean ...
, liver,
beef Beef is the culinary nameCulinary names, menu names, or kitchen names are names of foods used in the preparation or selling of food, as opposed to their names in agriculture Agriculture is the science, art and practice of cultivating pl ...

beef
kidneys,
brain A brain is an organ Organ may refer to: Biology * Organ (anatomy) An organ is a group of Tissue (biology), tissues with similar functions. Plant life and animal life rely on many organs that co-exist in organ systems. A given organ's tis ...

brain
s,
meat extract Meat extract is highly concentrated meat Meat is animal Animals (also called Metazoa) are multicellular eukaryotic organisms that form the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, ...
s (e.g.,
Oxo Oxo may refer to: Computing * '' OXO'', the first digital graphical computer game, a version of Tic-tac-toe from 1951 Business * Oxo (food) Oxo (stylized OXO) is a brand of food products, including stock cubes, herbs and spices, dried gr ...
,
Bovril Bovril is the trademarked name of a thick and salty meat extract Meat extract is highly concentrated meat stock (food), stock, usually made from beef. It is used to add meat flavour in cooking, and to make broth for soups and other liquid-bas ...

Bovril
),
herring Herring are forage fish Forage fish, also called prey fish or bait fish, are small pelagic fish which are preyed on by larger predators for food. Predators include other larger fish, seabirds and marine mammals. Typical ocean forage fish fee ...

herring
,
mackerel Mackerel is a common name applied to a number of different species of pelagic fish Pelagic fish live in the pelagic zone The pelagic zone consists of the water column A water column is a Concept, conceptual column of water from the ...

mackerel
,
scallop Scallop () is a common name Common may refer to: Places * Common, a townland in County Tyrone, Northern Ireland * Boston Common Boston Common (also known as the Common) is a central public park in downtown Boston, Massachusetts. It is some ...
s,
game meat Game or quarry is any wild animal Wildlife traditionally refers to undomesticated animal species (biology), species, but has come to include all organisms that grow or live wild in an area without being introduced species, introduced by ...
s,
beer Beer is one of the oldest and most widely consumed alcoholic drinks in the world, and the third most popular drink overall after water and tea. Beer is brewing, brewed from cereal, cereal grains—most commonly from malted barley, though wh ...

beer
(from the
yeast Yeasts are eukaryotic Eukaryotes () are organism In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular ...

yeast
) and
gravy Gravy is a sauce In , a sauce is a , , or semi- food, served on or used in preparing other s. Most sauces are not normally consumed by themselves; they add flavor, moisture, and visual appeal to a dish. ''Sauce'' is a word taken from the ...

gravy
. Some legumes, including
lentil The lentil (''Lens culinaris'' or ''Lens esculenta'') is an edible legume A legume () is a plant Plants are predominantly photosynthetic Photosynthesis is a process used by plants and other organisms to Energy transformation, co ...
s and black eye peas, are considered to be high purine plants. Foods and supplements containing spirulina can be exceptionally high in purines. A moderate amount of purine is also contained in red meat,
beef Beef is the culinary nameCulinary names, menu names, or kitchen names are names of foods used in the preparation or selling of food, as opposed to their names in agriculture Agriculture is the science, art and practice of cultivating pl ...

beef
,
pork Pork is the for the of the (''Sus scrofa domesticus''). It is the most commonly consumed meat worldwide, with evidence of pig dating back to 5000 BC. Pork is eaten both freshly cooked and preserved; extends the of pork products. , , , ...

pork
,
poultry Poultry () are domesticated Domestication is a sustained multi-generational relationship in which one group of organisms assumes a significant degree of influence over the reproduction and care of another group to secure a more predictable ...

poultry
, fish and
seafood Seafood is any form of sea life regarded as food by humans, prominently including fish Fish are , , -bearing animals that lack with . Included in this definition are the living , s, and and as well as various extinct related groups. ...

seafood
,
asparagus Asparagus, or garden asparagus, folk name sparrow grass, scientific name ''Asparagus officinalis'', is a perennial A perennial plant or simply perennial is a plant Plants are predominantly photosynthetic eukaryotes of the Kingdom ...

asparagus
,
cauliflower Cauliflower is one of several vegetables in the species ''Brassica oleracea ''Brassica oleracea'' is a plant species that includes many common foods as cultivars, including cabbage, broccoli, cauliflower, kale, Brussels sprouts, collard gre ...

cauliflower
,
spinach Spinach (''Spinacia oleracea'') is a leafy LEAFY (abbreviated LFY) is a plant Plants are predominantly photosynthetic Photosynthesis is a process used by plants and other organisms to Energy transformation, convert light energy int ...

spinach
,
mushrooms A mushroom or toadstool is the fleshy, spore )'', growing on a thinning, thinned hybrid black poplar ''(populus, Populus x canadensis)''. The last stage of the moss#Life cycle, moss lifecycle is shown, where the sporophytes are visible befor ...

mushrooms
, green peas,
lentil The lentil (''Lens culinaris'' or ''Lens esculenta'') is an edible legume A legume () is a plant Plants are predominantly photosynthetic Photosynthesis is a process used by plants and other organisms to Energy transformation, co ...
s, dried peas,
bean A bean is the seed of one of several of the , which are used as vegetables for human or animal food. They can be cooked in many different ways, including boiling, frying, and baking, and are used in many traditional dishes throughout th ...

bean
s,
oatmeal Oatmeal refers to a Rolled oats, preparation of oats that have been dehusked, Steaming, steamed and flattened, or else a coarse flour made of hulled oat grains (Groat (grain), groats) that have either been mill (grinding), milled (ground) or stee ...

oatmeal
,
wheat bran
wheat bran
,
wheat germ The germ of a cereal A cereal is any grass cultivated (grown) for the edible components of its grain A grain is a small, hard, dry seed, with or without an attached husk, hull or fruit layer, harvested for human or animal consumption. A gr ...
, and haws.


Biochemistry

Purines and
pyrimidine Pyrimidine is an aromatic In chemistry Chemistry is the scientific Science () is a systematic enterprise that builds and organizes knowledge Knowledge is a familiarity or awareness, of someone or something, such as facts ...

pyrimidine
s make up the two groups of
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 ...
s, including the two groups of
nucleotide bases 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 ...
. The purine nucleotide bases are
guanine Guanine () (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 me ...

guanine
(G) and
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
(A) which distinguish their corresponding
deoxyribonucleotide A deoxyribonucleotide 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, bonds. D ...
s (
deoxyadenosine Deoxyadenosine (symbol dA or dAdo) is a deoxyribonucleoside A deoxyribonucleoside is a type of nucleoside including deoxyribose as a component. An example is deoxycytidine. References {{organic-compound-stub Nucleosides, * .... It is a deriva ...
and
deoxyguanosine Deoxyguanosine is composed of the purine nucleobase guanine linked by its N9 nitrogen to the C1 carbon of deoxyribose. It is similar to guanosine, but with one hydroxyl group removed from the 2' position of the ribose sugar (making it deoxyribose) ...
) and
ribonucleotide In biochemistry, a ribonucleotide is a nucleotide containing ribose as its pentose component. It is considered a molecular precursor of nucleic acids. Nucleotides are the basic building blocks of DNA and RNA. Ribonucleotides themselves are basic mon ...
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
,
guanosine Guanosine (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 ...
). These nucleotides are
DNA Deoxyribonucleic acid (; DNA) is a molecule A scanning tunneling microscopy image of pentacene molecules, which consist of linear chains of five carbon rings. A molecule is an electrically Electricity is the set of physical ...

DNA
and
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
building blocks, respectively. Purine bases also play an essential role in many metabolic and signalling processes within the compounds
guanosine monophosphate Guanosine monophosphate (GMP), also known as 5′-guanidylic acid or guanylic acid (conjugate base A conjugate acid, within the Brønsted–Lowry acid–base theory The Brønsted–Lowry theory (also called proton theory of acids and bas ...
(GMP) and
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 up matter to the composed of s, s and s: their composition, structure, properties, behavior ...
(AMP). In order to perform these essential cellular processes, both purines and pyrimidines are needed by the
cell Cell most often refers to: * Cell (biology) The cell (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around ...
, and in similar quantities. Both purine and pyrimidine are self- inhibiting and activating. When purines are formed, they
inhibit Inhibitor or inhibition may refer to: In biology * Enzyme inhibitor 400px, An enzyme binding site that would normally bind substrate can alternatively bind a competitive inhibitor, preventing substrate access. Dihydrofolate reductase is inhi ...

inhibit
the
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
s required for more purine formation. This self-inhibition occurs as they also activate the enzymes needed for pyrimidine formation. Pyrimidine simultaneously self-inhibits and activates purine in similar manner. Because of this, there is nearly an equal amount of both substances in the cell at all times.


Properties

Purine is both a very weak acid ( pKa 8.93) and an even weaker base ( pKa 2.39). If dissolved in pure water, the
pH
pH
will be halfway between these two pKa values.


Notable purines

There are many naturally occurring purines. They include the
nucleobase 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 ...
s
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
(2) and
guanine Guanine () (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 me ...

guanine
(3). In
DNA Deoxyribonucleic acid (; DNA) is a molecule A scanning tunneling microscopy image of pentacene molecules, which consist of linear chains of five carbon rings. A molecule is an electrically Electricity is the set of physical ...

DNA
, these bases form
hydrogen bond A hydrogen bond (or H-bond) is a primarily electrostatic Electrostatics is a branch of physics Physics is the that studies , its , its and behavior through , and the related entities of and . "Physical science is that department ...

hydrogen bond
s with their
complementary A complement is often something that completes something else, or at least adds to it in some useful way. Thus it may be: * Complement (linguistics), a word or phrase having a particular syntactic role ** Subject complement, a word or phrase addi ...
pyrimidine Pyrimidine is an aromatic In chemistry Chemistry is the scientific Science () is a systematic enterprise that builds and organizes knowledge Knowledge is a familiarity or awareness, of someone or something, such as facts ...

pyrimidine
s,
thymine Thymine () (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 m ...

thymine
and
cytosine Cytosine () (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 ...

cytosine
, respectively. This is called complementary base pairing. In
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
, the complement of adenine is
uracil Uracil () (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 mea ...

uracil
instead of thymine. Other notable purines are
hypoxanthine Hypoxanthine is a naturally occurring purine Purine is a heterocyclic 125px, Pyridine, a heterocyclic compound A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different chemical element, elements ...

hypoxanthine
,
xanthine Xanthine ( or ; archaically xanthic acid; systematic name 3,7-dihydropurine-2,6-dione) is a purine Purine is a heterocyclic 125px, Pyridine, a heterocyclic compound A heterocyclic compound or ring structure is a cyclic compound that has ato ...

xanthine
,
theophylline Theophylline, also known as 1,3-dimethylxanthine, is a phosphodiesterase inhibiting drug used in therapy for respiratory disease Respiratory diseases, or lung diseases, are pathology, pathological conditions affecting the organs and tissues that ...

theophylline
,
theobromine Theobromine, also known as xantheose, is a bitter alkaloid Alkaloids are a class of base (chemistry), basic, natural product, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some relat ...

theobromine
,
caffeine Caffeine is a central nervous system The central nervous system (CNS) is the part of the nervous system In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structu ...

caffeine
,
uric acid Uric acid is a heterocyclic compound A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different chemical element, elements as members of its ring(s). Heterocyclic chemistry is the branch of orga ...

uric acid
and
isoguanine
isoguanine
. :


Functions

Aside from the crucial roles of purines (adenine and guanine) in DNA and RNA, purines are also significant components in a number of other important biomolecules, such as
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
, GTP,
cyclic AMP Cyclic adenosine monophosphate (cAMP, cyclic AMP, or 3',5'-cyclic adenosine monophosphate) is a second messenger important in many biological processes. cAMP is a derivative of adenosine triphosphate (ATP) and used for intracellular signal transd ...
,
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 ...
, and
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 ac ...
. Purine (1) itself, has not been found in nature, but it can be produced by
organic synthesis Organic synthesis is a special branch of chemical synthesis As a topic of , chemical synthesis (or combination) is the artificial execution of s to obtain one or several s. This occurs by and chemical manipulations usually involving one or mo ...

organic synthesis
. They may also function directly as
neurotransmitters A neurotransmitter is a signaling molecule In biology, cell signaling (cell signalling in British English), or cell-cell communication, governs the basic activities of cells and coordinates multiple-cell actions. A signal is an entity that ...

neurotransmitters
, acting upon purinergic receptors. Adenosine activates
adenosine receptor The adenosine receptors (or P1 receptors) are a class of purinergic G protein-coupled receptor G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine r ...
s.


History

The word ''purine'' (''pure urine'') was coined by the
German German(s) may refer to: Common uses * of or related to Germany * Germans, Germanic ethnic group, citizens of Germany or people of German ancestry * For citizens of Germany, see also German nationality law * German language The German la ...

German
chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin Medieval Latin was the form of Latin Latin (, or , ) is a classical language A classical language is a language A language is a structu ...

chemist
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 ...
in 1884. From p. 2550
''"…hielt ich es für zweckmäßig, alle diese Produkte ebenso wie die Harnsäure als Derivate der sauerstofffreien Verbindung C5H4N4 zu betrachten, und wählte für diese den Namen Purin, welcher aus den Wörtern purum und uricum kombiniert war."'' (…I regarded it as expedient to consider all of these products, just like uric acid, as derivatives of the oxygen-free compound C5H4N4, and chose for them the name "purine", which was formed from the atinwords ''purum'' and ''uricum''.)
He synthesized it for the first time in 1898. The starting material for the reaction sequence was
uric acid Uric acid is a heterocyclic compound A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different chemical element, elements as members of its ring(s). Heterocyclic chemistry is the branch of orga ...

uric acid
(8), which had been isolated from
kidney stone Kidney stone disease, also known as nephrolithiasis or urolithiasis, is when a calculus (medicine), solid piece of material (kidney stone) develops in the urinary tract. Kidney stones typically form in the kidney and leave the body in the urine ...
s by
Carl Wilhelm Scheele Carl Wilhelm Scheele (, ; 9 December 1742 – 21 May 1786) was a German and Swedish Pomerania Swedish Pomerania ( sv, Svenska Pommern; german: Schwedisch-Pommern) was a Dominion The word Dominion was used from 1907 to 1948 to refer to one o ...

Carl Wilhelm Scheele
in 1776. Uric acid (8) was reacted with to give 2,6,8-trichloropurine (10), which was converted with HI and PH4I to give 2,6-diiodopurine (11). The product was reduced to purine (1) using
zinc Zinc is a chemical element In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical element ...

zinc
dust. :


Metabolism

Many organisms have
metabolic pathway In biochemistry, a metabolic pathway is a linked series of chemical reactions occurring within a cell (biology), cell. The reactants, products, and intermediates of an enzymatic reaction are known as metabolites, which are modified by a sequence ...
s to synthesize and break down purines. Purines are biologically synthesized as
nucleoside Nucleosides are glycosylamine 120px, Cyclic hemiaminal ether bond derived from an aldehyde Glycosylamines are a class of biochemical compounds consisting of a Glycosyl, glycosyl group attached to an amine, amino group, -NR2. They are also known ...

nucleoside
s (bases attached to
ribose Ribose is a simple sugar and carbohydrate with molecular formula C5H10O5 and the linear-form composition H−(C=O)−(CHOH)4−H. The naturally-occurring form, , is a component of the ribonucleotides from which RNA is built, and so this compoun ...

ribose
). Accumulation of modified purine nucleotides is defective to various cellular processes, especially those involving
DNA Deoxyribonucleic acid (; DNA) is a molecule A scanning tunneling microscopy image of pentacene molecules, which consist of linear chains of five carbon rings. A molecule is an electrically Electricity is the set of physical ...

DNA
and
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
. To be viable, organisms possess a number of deoxypurine phosphohydrolases, which
hydrolyze Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution Substitution may refer to: Arts and media *Chord substitution, in music, swapping one chord fo ...
these purine derivatives removing them from the active NTP and
dNTP A nucleoside triphosphate is a molecule containing a nitrogenous base bound to a 5-carbon sugar (either ribose or deoxyribose), with three phosphate groups bound to the sugar. It is an example of a nucleotide. They are the molecular precursors of b ...
pools. Deamination of purine bases can result in accumulation of such nucleotides as ITP, dITP, and dXTP. Defects in enzymes that control purine production and breakdown can severely alter a cell's DNA sequences, which may explain why people who carry certain genetic variants of purine metabolic enzymes have a higher risk for some types of cancer.


Purine biosynthesis in the three domains of life

Organisms in all three domains of life, eukaryotes, bacteria and archaea, are able to carry out de novo biosynthesis of purines. This ability reflects the essentiality of purines for life. The biochemical pathway of synthesis is very similar in eukaryotes and bacterial species, but is more variable among archaeal species.Brown AM, Hoopes SL, White RH, Sarisky CA. Purine biosynthesis in archaea: variations on a theme. Biol Direct. 2011 Dec 14;6:63. doi: 10.1186/1745-6150-6-63. PMID 22168471; PMCID: PMC3261824 A nearly complete, or complete, set of genes required for purine biosynthesis was determined to be present in 58 of the 65 archaeal species studied. However, also identified were seven archaeal species with entirely, or nearly entirely, absent purine encoding genes. Apparently the archaeal species unable to synthesize purines are able to acquire exogenous purines for growth., and are thus analogous to purine mutants of eukaryotes, e.g. purine mutants of the Ascomycete fungus ''Neurospora crassa'', that also require exogenous purines for growth.


Relationship with gout

Higher levels of meat and
seafood Seafood is any form of sea life regarded as food by humans, prominently including fish Fish are , , -bearing animals that lack with . Included in this definition are the living , s, and and as well as various extinct related groups. ...

seafood
consumption are associated with an increased risk of gout, whereas a higher level of consumption of dairy products is associated with a decreased risk. Moderate intake of purine-rich vegetables or protein is not associated with an increased risk of gout. Similar results have been found with the risk of Hyperuricemia#Increased production of uric acid, hyperuricemia.


Laboratory synthesis

In addition to ''in vivo'' synthesis of purines in purine metabolism, purine can also be created artificially. Purine (1) is obtained in good yield when formamide is heated in an open vessel at 170 °C for 28 hours. : This remarkable reaction and others like it have been discussed in the context of abiogenesis, the origin of life. Patented Aug. 20, 1968, the current recognized method of industrial-scale production of adenine is a modified form of the formamide method. This method heats up formamide under 120 degree Celsius conditions within a sealed flask for 5 hours to form adenine. The reaction is heavily increased  in quantity by using a phosphorus oxychloride (phosphoryl chloride) or phosphorus pentachloride as an acid catalyst and sunlight or ultraviolet conditions. After the 5 hours have passed and the formamide-phosphorus oxychloride-adenine solution cools down, water is put into the flask containing the formamide and now-formed adenine. The water-formamide-adenine solution is then poured through a filtering column of activated charcoal. The water and formamide molecules, being small molecules, will pass through the charcoal and into the waste flask; the large adenine molecules, however, will attach or “adsorb” to the charcoal due to the van der waals forces that interact between the adenine and the carbon in the charcoal. Because charcoal has a large surface area, it's able to capture the majority of molecules that pass a certain size (greater than water and formamide) through it. To extract the adenine from the charcoal-adsorbed adenine, ammonia gas dissolved in water (aqua ammonia) is poured onto the activated charcoal-adenine structure to liberate the adenine into the ammonia-water solution. The solution containing water, ammonia, and adenine is then left to air dry, with the adenine losing solubility due to the loss of ammonia gas that previously made the solution basic and capable of dissolving adenine, thus causing it to crystallize into a pure white powder that can be stored. Oro, Orgel and co-workers have shown that four molecules of Hydrogen cyanide, HCN tetramerize to form diaminomaleonitrile, diaminomaleodinitrile (12), which can be converted into almost all naturally occurring purines. For example, five molecules of HCN condense in an exothermic reaction to make
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
, especially in the presence of ammonia. : The Traube purine synthesis (1900) is a classic reaction (named after Wilhelm Traube) between an amine-substituted
pyrimidine Pyrimidine is an aromatic In chemistry Chemistry is the scientific Science () is a systematic enterprise that builds and organizes knowledge Knowledge is a familiarity or awareness, of someone or something, such as facts ...

pyrimidine
and formic acid. :


Prebiotic synthesis of purine ribonucleosides

In order to understand how life arose, knowledge is required of the chemical pathways that permit formation of the key building blocks of life under plausible abiogenesis, prebiotic conditions. Nam et al. demonstrated the direct condensation of purine and pyrimidine nucleobases with ribose to give ribonucleosides in aqueous microdroplets, a key step leading to RNA formation. Also, a plausible prebiotic process for synthesizing purine ribonucleosides was presented by Becker et al.Becker S, Thoma I, Deutsch A, Gehrke T, Mayer P, Zipse H, Carell T. A high-yielding, strictly regioselective prebiotic purine nucleoside formation pathway. Science. 2016 May 13;352(6287):833-6. doi: 10.1126/science.aad2808. PMID 27174989.


See also

* Purinones * Pyrimidine * Simple aromatic rings * Transition (genetics), Transition * Transversion * Gout, a disorder of purine metabolism *Adenine *Guanine


References


External links


Purine Content in Food
{{Authority control Purines, Simple aromatic rings 1898 in science Emil Fischer