diphosphate-purine nucleoside kinase | |||||||||
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Identifiers | |||||||||
EC no. | 2.7.1.143 | ||||||||
CAS no. | 70356-41-1 | ||||||||
Databases | |||||||||
IntEnz | IntEnz view | ||||||||
BRENDA | BRENDA entry | ||||||||
ExPASy | NiceZyme view | ||||||||
KEGG | KEGG entry | ||||||||
MetaCyc | metabolic pathway | ||||||||
PRIAM | profile | ||||||||
PDB structures | RCSB PDB PDBe PDBsum | ||||||||
Gene Ontology | AmiGO / QuickGO | ||||||||
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In enzymology, a diphosphate-purine nucleoside kinase (EC 2.7.1.143) is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are diphosphate and purine nucleoside, whereas its two products are phosphate and purine mononucleotide.
This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing groups (phosphotransferases) with an alcohol group as acceptor. The systematic name of this enzyme class is diphosphate:purine nucleoside phosphotransferase. This enzyme is also called pyrophosphate-purine nucleoside kinase.
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 biochemistry, a kinase is an enzyme that catalyzes the transfer of phosphate groups from high-energy, phosphate-donating molecules to specific substrates. This process is known as phosphorylation, where the high-energy ATP molecule donates a phosphate group to the substrate molecule. This transesterification produces a phosphorylated substrate and ADP. Conversely, it is referred to as dephosphorylation when the phosphorylated substrate donates a phosphate group and ADP gains a phosphate group. These two processes, phosphorylation and dephosphorylation, occur four times during glycolysis.
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.
Diphosphate—fructose-6-phosphate 1-phosphotransferase also known as PFP is an enzyme of carbohydrate metabolism in plants and some bacteria. The enzyme catalyses the reversible interconversion of fructose 6-phosphate and fructose 1,6-bisphosphate using inorganic pyrophosphate as the phosphoryl donor:
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.
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.
Adenylate kinase is a phosphotransferase enzyme that catalyzes the interconversion of the various adenosine phosphates. By constantly monitoring phosphate nucleotide levels inside the cell, ADK plays an important role in cellular energy homeostasis.
Nucleoside-diphosphate kinases are enzymes that catalyze the exchange of terminal phosphate between different nucleoside diphosphates (NDP) and triphosphates (NTP) in a reversible manner to produce nucleotide triphosphates. Many NDP serve as acceptor while NTP are donors of phosphate group. The general reaction via ping-pong mechanism is as follows: XDP + YTP ←→ XTP + YDP. NDPK activities maintain an equilibrium between the concentrations of different nucleoside triphosphates such as, for example, when guanosine triphosphate (GTP) produced in the citric acid (Krebs) cycle is converted to adenosine triphosphate (ATP). Other activities include cell proliferation, differentiation and development, signal transduction, G protein-coupled receptor, endocytosis, and gene expression.
Purine nucleoside phosphorylase, PNP, PNPase or inosine phosphorylase is an enzyme that in humans is encoded by the NP gene. It catalyzes the chemical reaction
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.
Ribose-phosphate diphosphokinase is an enzyme that converts ribose 5-phosphate into phosphoribosyl pyrophosphate (PRPP). It is classified under EC 2.7.6.1.
In enzymology, a nucleoside-diphosphatase (EC 3.6.1.6) is an enzyme that catalyzes the chemical reaction
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