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.
In genetics and biochemistry, sequencing means to determine the primary structure of an unbranched biopolymer. Sequencing results in a symbolic linear depiction known as a sequence which succinctly summarizes much of the atomic-level structure of the sequenced molecule.
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 monomeric building blocks for RNA. Deoxyribonucleotides, formed by reducing ribonucleotides with the enzyme ribonucleotide reductase (RNR), are essential building blocks for DNA. There are several differences between DNA deoxyribonucleotides and RNA ribonucleotides. Successive nucleotides are linked together via phosphodiester bonds.
A nucleoside triphosphate is a nucleoside containing a nitrogenous base bound to a 5-carbon sugar, with three phosphate groups bound to the sugar. They are the molecular precursors of both DNA and RNA, which are chains of nucleotides made through the processes of DNA replication and transcription. Nucleoside triphosphates also serve as a source of energy for cellular reactions and are involved in signalling pathways.
Biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds, or joined to form macromolecules. This process often consists of metabolic pathways. Some of these biosynthetic pathways are located within a single cellular organelle, while others involve enzymes that are located within multiple cellular organelles. Examples of these biosynthetic pathways include the production of lipid membrane components and nucleotides. Biosynthesis is usually synonymous with anabolism.
Pyrosequencing is a method of DNA sequencing based on the "sequencing by synthesis" principle, in which the sequencing is performed by detecting the nucleotide incorporated by a DNA polymerase. Pyrosequencing relies on light detection based on a chain reaction when pyrophosphate is released. Hence, the name pyrosequencing.
Inosinic acid or inosine monophosphate (IMP) is a nucleotide. Widely used as a flavor enhancer, it is typically obtained from chicken byproducts or other meat industry waste. Inosinic acid is important in metabolism. It is the ribonucleotide of hypoxanthine and the first nucleotide formed during the synthesis of purine nucleotides. It can also be formed by the deamination of adenosine monophosphate by AMP deaminase. It can be hydrolysed to inosine.
Deoxycytidine triphosphate (dCTP) is a nucleoside triphosphate that contains the pyrimidine base cytosine. The triphosphate group contains high-energy phosphoanhydride bonds, which liberate energy when hydrolized.
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.
Deoxyadenosine triphosphate (dATP) is a nucleotide used in cells for DNA synthesis, as a substrate of DNA polymerase. It is classified as a purine nucleoside triphosphate, with its chemical structure consisting of a deoxyribose sugar molecule bound to an adenine and to three phosphate groups. It differs from the energy-transferring molecule adenosine triphosphate (ATP) by a single hydroxyl group, resulting in a deoxyribose instead of a ribose. Two phosphate groups can be hydrolyzed to yield deoxyadenosine monophosphate, which can then be used to synthesize DNA.
Purine metabolism refers to the metabolic pathways to synthesize and break down purines that are present in many organisms.
Adenylosuccinate is an intermediate in the interconversion of purine nucleotides inosine monophosphate (IMP) and adenosine monophosphate (AMP). The enzyme adenylosuccinate synthase carries out the reaction by the addition of aspartate to IMP and requires the input of energy from a phosphoanhydride bond in the form of guanosine triphosphate (GTP). GTP is used instead of adenosine triphosphate (ATP), so the reaction is not dependent on its products.
Xanthosine 5'-triphosphate (XTP) is a nucleotide that is not produced by - and has no known function in - living cells. Uses of XTP are, in general, limited to experimental procedures on enzymes that bind other nucleotides. Deamination of purine bases can result in accumulation of such nucleotides as ITP, dITP, XTP, and dXTP.
In enzymology, a nucleoside-diphosphatase (EC 3.6.1.6) is an enzyme that catalyzes the chemical reaction
In enzymology, a nucleoside-triphosphate diphosphatase (EC 3.6.1.19) is an enzyme that catalyzes the chemical reaction
In enzymology, an adenosine-phosphate deaminase (EC 3.5.4.17) is an enzyme that catalyzes the chemical reaction
In enzymology, a polynucleotide adenylyltransferase is an enzyme that catalyzes the chemical reaction
Inosine triphosphate pyrophosphatase is an enzyme that in humans is encoded by the ITPA gene, by the rdgB gene in bacteria E.coli and the HAM1 gene in yeast S. cerevisiae; the protein is also encoded by some RNA viruses of the Potyviridae family. Two transcript variants encoding two different isoforms have been found for this gene. Also, at least two other transcript variants have been identified which are probably regulatory rather than protein-coding.
Inosine-5'-monophosphate dehydrogenase 2, also known as IMP dehydrogenase 2, is an enzyme that in humans is encoded by the IMPDH2 gene.
DNA-deoxyinosine glycosylase is an enzyme with systematic name DNA-deoxyinosine deoxyribohydrolase. This enzyme is involved in DNA damage repair and targets hypoxanthine bases.
