Nucleotides are organic molecules composed of a nitrogenous base, a pentose sugar and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules within all life-forms on Earth. Nucleotides are obtained in the diet and are also synthesized from common nutrients by the liver.
Uridine (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. The analog is one of the five standard nucleosides which make up nucleic acids, the others being adenosine, thymidine, cytidine and guanosine. The five nucleosides are commonly abbreviated to their symbols, U, A, dT, C, and G, respectively. However, thymidine is more commonly written as 'dT' ('d' represents 'deoxy') as it contains a 2'-deoxyribofuranose moiety rather than the ribofuranose ring found in uridine. This is because thymidine is found in deoxyribonucleic acid (DNA) and usually not in ribonucleic acid (RNA). Conversely, uridine is found in RNA and not DNA. The remaining three nucleosides may be found in both RNA and DNA. In RNA, they would be represented as A, C and G whereas in DNA they would be represented as dA, dC and dG.
Uridine-5′-triphosphate (UTP) is a pyrimidine nucleoside triphosphate, consisting of the organic base uracil linked to the 1′ carbon of the ribose sugar, and esterified with tri-phosphoric acid at the 5′ position. Its main role is as substrate for the synthesis of RNA during transcription. UTP is the precursor for the production of CTP via CTP synthetase. UTP can be biosynthesized from UDP by Nucleoside Diphosphate Kinase after using the phosphate group from ATP. UDP + ATP ⇌ UTP + ADP; both UTP and ATP are energetically equal.
Glucose 6-phosphate is a glucose sugar phosphorylated at the hydroxy group on carbon 6. This dianion is very common in cells as the majority of glucose entering a cell will become phosphorylated in this way.
A salvage pathway is a 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 nucleotides are synthesized from intermediates in their degradative pathway.
Glycogenesis is the process of glycogen synthesis, in which glucose molecules are added to chains of glycogen for storage. This process is activated during rest periods following the Cori cycle, in the liver, and also activated by insulin in response to high glucose levels.
Glucose 1-phosphate is a glucose molecule with a phosphate group on the 1'-carbon. It can exist in either the α- or β-anomeric form.
Glycogen synthase is a key enzyme in glycogenesis, the conversion of glucose into glycogen. It is a glycosyltransferase that catalyses the reaction of UDP-glucose and n to yield UDP and n+1.
Nucleic acid metabolism is a collective term that refers to the variety of chemical reactions by which nucleic acids are either synthesized or degraded. Nucleic acids are polymers made up of a variety of monomers called nucleotides. Nucleotide synthesis is an anabolic mechanism generally involving the chemical reaction of phosphate, pentose sugar, and a nitrogenous base. Degradation of nucleic acids is a catabolic reaction and the resulting parts of the nucleotides or nucleobases can be salvaged to recreate new nucleotides. Both synthesis and degradation reactions require multiple enzymes to facilitate the event. Defects or deficiencies in these enzymes can lead to a variety of diseases.
Uridine diphosphate glucose is a nucleotide sugar. It is involved in glycosyltransferase reactions in metabolism.
UTP—glucose-1-phosphate uridylyltransferase also known as glucose-1-phosphate uridylyltransferase is an enzyme involved in carbohydrate metabolism. It synthesizes UDP-glucose from glucose-1-phosphate and UTP; i.e.,
Deoxyuridine monophosphate (dUMP), also known as deoxyuridylic acid or deoxyuridylate in its conjugate acid and conjugate base forms, respectively, is a deoxynucleotide.
The enzyme UDP-glucuronate decarboxylase (EC 4.1.1.35) catalyzes the chemical reaction
Nucleotide sugars are the activated forms of monosaccharides. Nucleotide sugars act as glycosyl donors in glycosylation reactions. Those reactions are catalyzed by a group of enzymes called glycosyltransferases.
In enzymology, a glucose-1-phosphate adenylyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, a glucuronate-1-phosphate uridylyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, an UDP-N-acetylglucosamine diphosphorylase is an enzyme that catalyzes the chemical reaction
In enzymology, an UTP—hexose-1-phosphate uridylyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, an UTP-monosaccharide-1-phosphate uridylyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, an UTP—xylose-1-phosphate uridylyltransferase is an enzyme that catalyzes the chemical reaction
