Uracil is a common and naturally occurring
pyrimidinePyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 and 3 of the six-member ring...
derivative. Originally discovered in 1900, it was isolated by
hydrolysisHydrolysis is a chemical reaction during which one or more water molecules are split into hydrogen and hydroxide ions, which may go on to participate in further reactions. It is the type of reaction that is used to break down certain polymers, especially those made by step-growth polymerization...
of
yeastYeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with about 1,500 species currently described; they dominate fungal diversity in the oceans. Most reproduce asexually by budding, although a few do so by binary fission...
nuclein that was found in bovine
thymusIn human anatomy, the thymus is an organ located in the upper anterior portion of the chest cavity just behind the sternum. The main function of the thymus is to provide an area for T lymphocyte maturation, and is vital in protecting against autoimmunity....
and
spleenThe spleen is an organ found in virtually all vertebrate animals with important roles in regard to red blood cells and the immune system In humans, it is located in the left upper quadrant of the abdomen. It removes old red blood cells, holds a reserve in case of hemorrhagic shock, especially in...
,
herringHerring are relatively small oily fish of the genus Clupea found in the shallow, temperate waters of the North Pacific and the North Atlantic oceans, including the Baltic Sea. Two species of Clupea are currently recognized, the Atlantic herring and the Pacific herring , each of which may be...
spermThe term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...
, and
wheatWheat is a worldwide cultivated grass from the Fertile Crescent region of the Near East. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...
germGerm may refer to:* Microorganism, especially a pathogen; see Germ theory of disease* Germ cell, an ovum or sperm, or one of its progenitors* The Germ , a periodical established by the Pre-Raphaelite Brotherhood to disseminate their ideas...
. It is a planar, unsaturated compound that has the ability to absorb light.
Found in
RNARibonucleic acid is a biologically important type of molecule that consists of a long chain of nucleotide units. Each nucleotide consists of a nitrogenous base, a ribose sugar, and a phosphate...
, it
base pairIn molecular biology, two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds are called a base pair . In the canonical Watson-Crick base pairing, adenine forms a base pair with thymine , as does guanine with cytosine in DNA. In RNA, thymine is replaced...
s with
adenineAdenine 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...
and replaces
thymineThymine is one of the four nucleobases in the nucleic acid of DNA that are represented by the letters G–C–A–T. The others are adenine, guanine, and cytosine. Thymine always pairs with adenine. Thymine is also known as 5-methyluracil, a pyrimidine nucleobase. As the name suggests, thymine may be...
during
DNADeoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information...
transcription. Methylation of uracil produces
thymineThymine is one of the four nucleobases in the nucleic acid of DNA that are represented by the letters G–C–A–T. The others are adenine, guanine, and cytosine. Thymine always pairs with adenine. Thymine is also known as 5-methyluracil, a pyrimidine nucleobase. As the name suggests, thymine may be...
.
Uracil is a common and naturally occurring
pyrimidinePyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 and 3 of the six-member ring...
derivative. Originally discovered in 1900, it was isolated by
hydrolysisHydrolysis is a chemical reaction during which one or more water molecules are split into hydrogen and hydroxide ions, which may go on to participate in further reactions. It is the type of reaction that is used to break down certain polymers, especially those made by step-growth polymerization...
of
yeastYeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with about 1,500 species currently described; they dominate fungal diversity in the oceans. Most reproduce asexually by budding, although a few do so by binary fission...
nuclein that was found in bovine
thymusIn human anatomy, the thymus is an organ located in the upper anterior portion of the chest cavity just behind the sternum. The main function of the thymus is to provide an area for T lymphocyte maturation, and is vital in protecting against autoimmunity....
and
spleenThe spleen is an organ found in virtually all vertebrate animals with important roles in regard to red blood cells and the immune system In humans, it is located in the left upper quadrant of the abdomen. It removes old red blood cells, holds a reserve in case of hemorrhagic shock, especially in...
,
herringHerring are relatively small oily fish of the genus Clupea found in the shallow, temperate waters of the North Pacific and the North Atlantic oceans, including the Baltic Sea. Two species of Clupea are currently recognized, the Atlantic herring and the Pacific herring , each of which may be...
spermThe term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...
, and
wheatWheat is a worldwide cultivated grass from the Fertile Crescent region of the Near East. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...
germGerm may refer to:* Microorganism, especially a pathogen; see Germ theory of disease* Germ cell, an ovum or sperm, or one of its progenitors* The Germ , a periodical established by the Pre-Raphaelite Brotherhood to disseminate their ideas...
. It is a planar, unsaturated compound that has the ability to absorb light.
Properties
Found in
RNARibonucleic acid is a biologically important type of molecule that consists of a long chain of nucleotide units. Each nucleotide consists of a nitrogenous base, a ribose sugar, and a phosphate...
, it
base pairIn molecular biology, two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds are called a base pair . In the canonical Watson-Crick base pairing, adenine forms a base pair with thymine , as does guanine with cytosine in DNA. In RNA, thymine is replaced...
s with
adenineAdenine 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...
and replaces
thymineThymine is one of the four nucleobases in the nucleic acid of DNA that are represented by the letters G–C–A–T. The others are adenine, guanine, and cytosine. Thymine always pairs with adenine. Thymine is also known as 5-methyluracil, a pyrimidine nucleobase. As the name suggests, thymine may be...
during
DNADeoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information...
transcription. Methylation of uracil produces
thymineThymine is one of the four nucleobases in the nucleic acid of DNA that are represented by the letters G–C–A–T. The others are adenine, guanine, and cytosine. Thymine always pairs with adenine. Thymine is also known as 5-methyluracil, a pyrimidine nucleobase. As the name suggests, thymine may be...
. It turns into thymine to protect the DNA and to improve the efficiency of
DNA replicationDNA replication, the basis for biological inheritance, is a fundamental process occurring in all living organisms to copy their DNA. This process is "semiconservative" in that each strand of the original double-stranded DNA molecule serves as template for the reproduction of the complementary strand...
. Uracil can base pair with any of the bases depending on how the molecule arranges itself on the
helixA helix is a special kind of space curve, i.e. a smooth curve in three-space. As a mental image of a helix one may take the spring...
, but readily pairs with
adenineAdenine 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...
because the methyl group is repelled into a fixed position. Uracil pairs with adenine through hydrogen bonding. Uracil is the hydrogen bond acceptor and can form two hydrogen bonds. Uracil can also bind with a
riboseRibose, primarily occurring as
D-ribose, is an organic compound that occurs widely in nature. It is an aldopentose, that is a monosaccharide containing five carbon atoms that, in its acyclic form, has an aldehyde functional group at one end. This species predominantly exists in the...
sugar to form a
ribonucleosideA ribonucleoside is a type of nucleoside including ribose as a component.An example is cytidine....
,
uridineUridine is a molecule that is formed when uracil is attached to a ribose ring via a β-N
1-glycosidic bond.If uracil is attached to a deoxyribose ring, it is known as a deoxyuridine....
. When a
phosphateA 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...
attaches to uridine, uridine 5'-monophosphate is produced.
Uracil undergoes amide-imidic acid tautomeric shifts because any nuclear instability the molecule may have from the lack of formal
aromaticityIn organic chemistry, the structures of some rings of atoms are unexpectedly stable. Aromaticity is a chemical property in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibit a stabilization stronger than would be expected by the stabilization of conjugation alone...
is compensated by the cyclic-amidic stability. The amide
tautomerTautomers are isomers of organic compounds that readily interconvert by a chemical reaction called tautomerization. It is common that this reaction results in the formal migration of a hydrogen atom or proton, accompanied by a switch of a single bond and adjacent double bond. In solutions in which...
is referred to the
lactamA lactam is a cyclic amide. Prefixes indicate how many carbon atoms are present in the ring: β-lactam , γ-lactam , δ-lactam...
structure, while the imidic acid tautomer is referred to as the
lactimLactim is a cyclic carboximidic acid compound characterized by an endocyclic carbon-nitrogen double bond. It is tautomeric with lactam....
structure. These tautomeric forms are predominant at
pHpH is a measure of the acidity or basicity of a solution. It is defined as the cologarithm of the activity of dissolved hydrogen ions . Hydrogen ion activity coefficients cannot be measured experimentally, so they are based on theoretical calculations...
=7. The lactam structure is the most common form of uracil.
Uracil also recycles itself to form nucleotides by undergoing a series of phosphoribosyltransferase reactions. Degradation of uracil produces substrates, aspartate,
carbon dioxideCarbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state...
, and
ammoniaAmmonia is a compound of nitrogen and hydrogen with the formula NH
3. It is normally encountered as a gas with a characteristic pungent odor. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to foodstuffs and fertilizers...
.
- C4H4N2O2 → H3NCH2CH2COO- + NH4 + CO2
Oxidative degradation of uracil produces urea and maleic acid in the presence of
H2O2Hydrogen peroxide is a very pale blue liquid, slightly more viscous than water, that appears colorless in dilute solution. It is a weak acid, has strong oxidizing properties, and is a powerful bleaching agent. It is used as a disinfectant, antiseptic, oxidizer, and in rocketry as a propellant...
and
FeFe may refer to:*Fantasy Empires, a 1993 Dungeons & Dragons computer game*Fast Ethernet*Fe , The debut album by Souled American*Fe , the f-rune, of the Younger Futhark*"Fe" , a song by Jorge González...
2+ or in the presence of diatomic
oxygenOxygen Oxygen Oxygen (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter) is the element with atomic number 8 and represented by the symbol O...
and Fe
2+.
Uracil is a
weak acidA weak acid is an acid that dissociates incompletely and does not release all of its hydrogens in a solution i.e it does not completely donate all of its protons. These acids have higher pKa compared to strong acids, which release all of their hydrogens when dissolved in water.While strong acids...
, the first site of
ionizationIonization is the physical process of converting an atom or molecule into an ion by adding or removing charged particles such as electrons or other ions. This is often confused with dissociation ....
of uracil is not known. The negative charge is placed on the oxygen anion and produces a
pKaAn acid dissociation constant, Ka, is a quantitative measure of the strength of an acid in solution. It is the equilibrium constant for a chemical reaction known as dissociation in the context of acid-base reactions...
of less than or equal to 12. The basic pK
a = -3.4, while the acidic pK
a = 9.38
9. In the gas phase, uracil has 4 sites that are more acidic than water.
Synthesis
There are many laboratory synthesesIn chemistry, chemical synthesis is purposeful execution of chemical reactions to get a product, or several products. This happens by physical and chemical manipulations usually involving one or more reactions...
of uracil available. The first reaction is the simplest of the syntheses, by adding water to cytosineCytosine is one of the four main bases found in DNA and RNA. It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached . The nucleoside of cytosine is cytidine...
to produce uracil and ammoniaAmmonia is a compound of nitrogen and hydrogen with the formula NH
3. It is normally encountered as a gas with a characteristic pungent odor. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to foodstuffs and fertilizers...
. The most common way to synthesize uracil is by the condensationCondensation is the change of the physical state of aggregation of matter from gaseous phase into liquid phase and the reverse of evaporation. When the transition happens from the gaseous phase into the solid phase directly, bypassing the liquid phase, the change is called deposition...
of maleic acidMaleic acid or -butenedioic acid or cis-butenedioic acid. is an organic compound that is a dicarboxylic acid...
with urea in fuming sulfuric acid as seen below also. Uracil can also be synthesized by a double decomposition of thiouracilThiouracil refers both to a specific molecule consisting of a sulfated uracil, and a family of molecules based upon that structure. The substance is a historically relevant antithyroid preparation; Astwood E.B. used it in 1943 as therapy of the Graves' disease for the first time....
in aqueous chloroacetic acidChloroacetic acid is the chemical compound with the formula ClCH2CO2H. This carboxylic acid is a useful building block in organic synthesis...
.
- C4H5N3O + H2O → C4H4N2O2 + NH3
- C4H4O4 + CH4N2O → C4H4N2O2 + 2 H2O + CO
Photodehydrogenation of 5,6-diuracil, which is synthesized by beta-alanineAlanine is an α-amino acid with the chemical formula CH3CHCOOH. The L-isomer is one of the 20 proteinogenic amino acids, i.e. the building blocks of proteins. Its codons are GCU, GCC, GCA, and GCG. It is classified as a nonpolar amino acid...
reacting with ureaUrea or carbamide is an organic compound with the chemical formula
2CO. The molecule has two amine residues joined by a carbonyl functional group....
, produces uracil.
Reactions
Uracil readily undergoes regular reactions including oxidation, nitrationNitration is a general chemical process for the introduction of a nitro group into a chemical compound. Examples of nitrations are the conversion of glycerin to nitroglycerin and the conversion of toluene to trinitrotoluene...
, and alkylationAlkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion or a carbene . Alkylating agents are widely used in chemistry because the alkyl group is probably the most common group encountered in...
. While in the presence of PhOHPhenol, also known as carbolic acid, is a toxic, white crystalline solid. Its chemical formula is C6H5OH and its structure is that of a hydroxyl group bonded to a phenyl ring, making it an aromatic compound.-Phenols:...
/NaOClSodium hypochlorite is a chemical compound with the formula NaClO. Sodium hypochlorite solution, commonly known as bleach, is frequently used as a disinfectant or a bleaching agent.-Production:...
, uracil can be visualized in the blue region of UV light. Uracil also has the capability to react with elemental halogenThe halogens or halogen elements are a series of nonmetal elements from Group 17 IUPAC Style of the periodic table, comprising fluorine, ; chlorine, ; bromine, ; iodine, ; and astatine,...
s because of the presence of more than one strongly electron donating group.
Uracil readily undergoes addition to riboseRibose, primarily occurring as
D-ribose, is an organic compound that occurs widely in nature. It is an aldopentose, that is a monosaccharide containing five carbon atoms that, in its acyclic form, has an aldehyde functional group at one end. This species predominantly exists in the...
sugarSugar is a class of edible crystalline substances, mainly sucrose, lactose, and fructose. Human taste buds interpret its flavor as sweet. Sugar as a basic food carbohydrate primarily comes from sugar cane and from sugar beet, but also appears in fruit, honey, sorghum, sugar maple , and in many...
s and phosphateA 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...
s to partake in synthesis and further reactions in the body. Uracil becomes uridineUridine is a molecule that is formed when uracil is attached to a ribose ring via a β-N
1-glycosidic bond.If uracil is attached to a deoxyribose ring, it is known as a deoxyuridine....
, uridine monophosphateUridine monophosphate, also known as 5'-uridylic acid and abbreviated UMP, is a nucleotide that is found in RNA. It is an ester of phosphoric acid with the nucleoside uridine...
(UMP), uridine diphosphateUridine diphosphate, abbreviated UDP, is a nucleotide. It is an ester of pyrophosphoric acid with the nucleoside uridine. UDP consists of the pyrophosphate group, the pentose sugar ribose, and the nucleobase uracil.- See also :* Nucleoside...
(UDP), uridine triphosphate (UTP), and uridine diphosphate glucoseUridine diphosphate glucose is a nucleotide sugar. It is involved in glycosyltransferase reactions in metabolism.-Functions:...
(UDP-glucose). Each one of these molecules in synthesized in the body and has specific functions.
When uracil reactes with anhydrous hydrazineHydrazine is an inorganic chemical compound with the formula N2H4. It is a colourless liquid with an ammonia-like odor and is derived from the same industrial chemistry processes that manufacture ammonia...
a first order kinetic reaction occurs and the ring of uracil opens up. If the pH of the reaction increases to >10.5 the uracil anion forms making the reaction go much slower, the same slowing of the reaction occurs if the pH decreases because of the protonation of the hydrazine. The reactivity of uracil is unchanged even if the temperature changes.
Uses
Uracil can be used for drug deliveryDrug delivery is the method or process of administering a pharmaceutical compound to achieve a therapeutic effect in humans or animals. Drug delivery technologies are patent protected formulation technologies that modify drug release profile, absorption, distribution and elimination for the benefit...
and as a pharmaceutical. When elemental fluorineFluorine is the chemical element with atomic number 9, represented by the symbol F. Fluorine forms a single bond with itself in elemental form, resulting in the diatomic F
2 molecule. F
2 is a supremely reactive, poisonous, pale, yellowish brown gas. Elemental fluorine is the...
is reacted with uracil, 5-fluorouracil is produced. 5-Fluorouracil is an anticancer drug (antimetaboliteAn antimetabolite is a chemical that inhibits the use of a metabolite, which is another chemical that is part of normal metabolism. Such substances are often similar in structure to the metabolite that they interfere with, such as the antifolates that interfere with the use of folic acid...
) used to masquerade-Events:* Masquerade ball, a costumed dance event* Masquerade ceremony, a rite or cultural event in many parts of world* Masqueraders, the performers in the West Country Carnival-Book:...
as uracil during the nucleic acid replication process. Because 5-Fluorouracil is similar in shape to, but does not perform the same chemistry as uracil the drug inhibits RNARibonucleic acid is a biologically important type of molecule that consists of a long chain of nucleotide units. Each nucleotide consists of a nitrogenous base, a ribose sugar, and a phosphate...
replication enzymes, thereby eliminating RNA synthesis and stopping the growth of cancerous cells.
Uracil's use in the body is to help carry out the synthesis of many enzymes necessary for cell function through bonding with riboses and phosphates. Uracil serves as allosteric regulator and coenzyme for reactions in the human body and in plants. UMP controls the activity of carbamoyl phosphate synthetaseCarbamoyl phosphate synthetase is an enzyme that catalyzes a reaction that produces carbamoyl phosphate. This enzyme catalyzes the reaction of ATP and bicarbonate to produce carbonyl phosphate and ADP. Carbonyl phosphate reacts with ammonia to give carbamate...
and aspartate transcarbamoylase in plants, while UDP and UTP requlate CPSase II activity in animalAnimals are a major group of mostly multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously...
s. UDP-glucose regulates the conversion of glucoseGlucose , a monosaccharide also known as - grape sugar, blood sugar, or corn sugar, is a very important carbohydrate in biology. The living cell uses it as a source of energy and metabolic intermediate...
to galactoseGalactose is a type of sugar which is less sweet than glucose. It is considered a nutritive sweetener because it has food energy. Its name comes from the Ancient Greek word for milk, γάλακτος ....
in the liverThe liver is a vital organ present in vertebrates and some other animals; it has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
and other tissues in the process of carbohydrate metabolismCarbohydrate metabolism denotes the various biochemical processes responsible for the formation, breakdown and interconversion of carbohydrates in living organisms....
. Uracil is also involved in the biosynthesisBiosynthesis is an enzyme-catalyzed process in cells of living organisms by which substrates are converted to more complex products. The biosynthesis process often consists of several enzymatic steps in which the product of one step is used as substrate in the following step...
of polysaccharides and the transportation of sugars containing aldehydes.
It can also increase the risk for cancer in cases where the body is extremely deficient in folate. The deficiency in folate leads to increased ratio of deoxyuracilmonophosphates (dUMP)/deoxythyminemonophosphates (dTMP) and uracil misincorporation into DNA and eventually low production of DNA.
Uracil can be used to determine microbial contamination of tomatoThe tomato is a herbaceous, usually sprawling plant in the Solanaceae or nightshade family that is typically cultivated for the purpose of harvesting its fruit for human consumption...
es. The presence of uracil is an indication of lactic acidLactic acid , also known as milk acid, is a chemical compound that plays a role in several biochemical processes. It was first isolated in 1780 by a Swedish chemist, Carl Wilhelm Scheele, and is a carboxylic acid with a chemical formula of C
3H
6O
3...
bacteriaThe bacteria are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
contamination in the fruit. Uracil derivatives containing a diazineDiazine refers to a group of organic compounds having the molecular formula C
4H
4N
2. Each contains a benzene ring in which two of the C-H fragments have been replaced by isolobal nitrogen...
ring are used in pesticides. Uracil derivatives are more often used as antiphotosynthetic herbicides, destroying weeds in cottonCotton is a soft, staple fiber that grows in a form known as a boll around the seeds of the cotton plant, a shrub native to tropical and subtropical regions around the world, including the Americas, India and Africa. The fiber most often is spun into yarn or thread and used to make a soft,...
, sugar beetSugar beet , a member of the Chenopodiaceae family, is a plant whose root contains a high concentration of sucrose. It is grown commercially for sugar production....
, turnips, soyaThe soybean or soya bean is a species of legume native to East Asia. The plant is classed as an oilseed rather than a pulse. It is an annual plant that has been used in China for 5,000 years to primarily add nitrogen into the soil as part of crop rotation...
, peasP.E.A.S. is an acronym in artificial intelligence that stands for Performance, Environment, Actuators, Sensors.-Environment:The environment in which the agent operates. They are the described with the following main properties:...
, sunflowerSunflowers are annual plants native to the Americas, that possess a large inflorescence .-Description :...
crops, vineyards, berryThe botanical definition of a berry is a simple fruit produced from a single ovary, such as a grape or a tomato. The berry is the most common type of fleshy fruit in which the entire ovary wall ripens into an edible pericarp. The flowers of these plants have a superior ovary formed by the fusion of...
plantations, and orchards.