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Purine is a heterocyclic aromatic organic compound that consists of two rings (pyrimidine and imidazole) fused together. It is water-soluble. Purine also gives its name to the wider class of molecules, purines, which include substituted purines and their tautomers. They are the most widely occurring nitrogen-containing heterocycles in nature. [1]
Purines are biologically synthesized as nucleotides and in particular as ribotides, i.e. bases attached to ribose 5-phosphate.Both adenine and guanine are derived from the nucleotide inosine monophosphate (IMP), which is the first compound in the pathway to have a completely formed purine ring system.
n/a Ensembl n/a n/a UniProt n a n/a RefSeq (mRNA) n/a n/a RefSeq (protein) n/a n/a Location (UCSC) n/a n/a PubMed search n/a n/a Wikidata View/Edit Human Purine nucleoside phosphorylase, PNP, PNPase or inosine phosphorylase (EC 2.4.2.1) is an enzyme that in humans is encoded by the NP gene. It catalyzes the chemical reaction purine nucleoside + phosphate ⇌ {\displaystyle \rightleftharpoons ...
Purinergic signalling (or signaling: see American and British English differences) is a form of extracellular signalling mediated by purine nucleotides and nucleosides such as adenosine and ATP. It involves the activation of purinergic receptors in the cell and/or in nearby cells, thereby regulating cellular functions.
Depurination is not uncommon because purine is a good leaving group via the 9N-nitrogen (see the structure of a purine).Furthermore, the anomeric carbon is especially reactive towards nucleophilic substitution (effectively making the carbon-oxygen bond shorter, stronger and more polar, while making the carbon-purine bond longer and weaker).
In enzymology, a purine nucleosidase (EC 3.2.2.1) is an enzyme that catalyzes the chemical reaction a purine nucleoside + H 2 O ⇌ {\displaystyle \rightleftharpoons } D-ribose + a purine base Thus, the two substrates of this enzyme are purine nucleoside and H 2 O , whereas its two products are D-ribose and purine base .
Purine metabolism involves the formation of adenine and guanine. Both adenine and guanine are derived from the nucleotide inosine monophosphate (IMP), which in turn is synthesized from a pre-existing ribose phosphate through a complex pathway using atoms from the amino acids glycine , glutamine , and aspartic acid , as well as the coenzyme ...
Xanthine (/ ˈ z æ n θ iː n / or / ˈ z æ n θ aɪ n /, from Ancient Greek ξανθός xanthós ' yellow ' for its yellowish-white appearance; archaically xanthic acid; systematic name 3,7-dihydropurine-2,6-dione) is a purine base found in most human body tissues and fluids, as well as in other organisms. [2]