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uracil(yo͝or`əsĭl), organic base of the pyrimidinepyrimidine
, type of organic base found in certain coenzymes and in the nucleic acids of plant and animal tissue. The three major pyrimidines of almost universal distribution in living systems are cytosine, thymine, and uracil.
..... Click the link for more information. family. It was isolated from herring sperm and also produced in a laboratory in 1900–1901. When combined with the sugar ribose in a glycosidic linkage, uracil forms a derivative called uridine (a nucleoside), which in turn can be phosphorylated with from one to three phosphoric acid groups, yielding respectively the three nucleotidesnucleotide
, organic substance that serves as a monomer in forming nucleic acids. Nucleotides consist of either a purine or a pyrimidine base, a ribose or deoxyribose, and a phosphate group. Adenosine triphosphate serves as the principle energy carrier for the cell's reactions.
..... Click the link for more information. UMP (uridine monophosphate), UDP (uridine diphosphate), and UTP (uridine triphosphate). The analogous nucleosides and nucleotides formed from uridine and deoxyribose occur only very rarely in living systems; such is not the case with the other pyrimidines. The nucleotide derivatives of uracil perform important functions in cellular metabolism, particularly in carbohydrate metabolism; UTP acts as a coenzymecoenzyme
, any one of a group of relatively small organic molecules required for the catalytic function of certain enzymes. A coenzyme may either be attached by covalent bonds to a particular enzyme or exist freely in solution, but in either case it participates intimately in
..... Click the link for more information. in the biosynthesis of sucrose in plants, lactose and glycogen in mammals, and chitin in insects. It can also readily donate one of its phosphate groups to adenosine diphosphate (ADP) to form adenosine triphosphateadenosine triphosphate
(ATP) , organic compound composed of adenine, the sugar ribose, and three phosphate groups. ATP serves as the major energy source within the cell to drive a number of biological processes such as photosynthesis, muscle contraction, and the synthesis of
..... Click the link for more information. (ATP), an extremely important intermediate in the transfer of chemical energy in living cells. Since the uracil nucleotides contain only ribose and not deoxyribose, UTP is the source of uridine only in ribonucleic acid (RNA); there is no uridine in deoxyribonucleic acid (DNA). Its involvement in the biosynthesis of RNA demonstrates that uracil is important in the translation of genetic information (see nucleic acidnucleic acid,
any of a group of organic substances found in the chromosomes of living cells and viruses that play a central role in the storage and replication of hereditary information and in the expression of this information through protein synthesis.
..... Click the link for more information. ). A few laboratory derivatives of uracil have been designed as experimental antimetabolites (see metabolitemetabolite,
organic compound that is a starting material in, an intermediate in, or an end product of metabolism. Starting materials are substances, usually small and of simple structure, absorbed by the organism as food. These include the vitamins and essential amino acids.
..... Click the link for more information. ) for use in cancer chemotherapy.
(also 2, 6-dioxypyrimidine), an organic substance and pyrimidine. Uracil occurs either as a white powder or as crystalline needles; it is soluble in hot water, has a molecular weight of 112, and is amphoteric and tautomeric:
Uracil was discovered in 1900, when it was detected in the products resulting from the breakdown of yeast nucleic acids. It is present in all living cells, forming part of many nucleotides and ribonucleic acids.