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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]
[1] [2] HGPRT is a transferase that catalyzes conversion of hypoxanthine to inosine monophosphate and guanine to guanosine monophosphate. This reaction transfers the 5-phosphoribosyl group from 5-phosphoribosyl 1-pyrophosphate (PRPP) to the purine. HGPRT plays a central role in the generation of purine nucleotides through the purine salvage ...
Formyl groups build carbon-2 and carbon-8 in the purine ring system, which are the ones acting as bridges between two nitrogen atoms. A key regulatory step is the production of 5-phospho-α-D-ribosyl 1-pyrophosphate by ribose-phosphate diphosphokinase, which is activated by inorganic phosphate and inactivated by purine ribonucleotides. It is ...
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]
[1] [5] ATP, a purine nucleotide, is an activator of pyrimidine synthesis, while CTP, a pyrimidine nucleotide, is an inhibitor of pyrimidine synthesis. This regulation helps to keep the purine/pyrimidine amounts similar, which is beneficial because equal amounts of purines and pyrimidines are required for DNA synthesis. [1] [6]
[1] [2] It is classified under EC 2.7.6.1. The enzyme is involved in the synthesis of nucleotides ( purines and pyrimidines ), cofactors NAD and NADP , and amino acids histidine and tryptophan , [ 1 ] [ 2 ] [ 3 ] linking these biosynthetic processes to the pentose phosphate pathway, from which the substrate ribose 5-phosphate is derived.
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 ...
The nitrogenous bases are either purines or pyrimidines, heterocycles whose structures support the specific base-pairing interactions that allow nucleic acids to carry information. The base is always bonded to the 1'-carbon of the deoxyribose, an analog of ribose in which the hydroxyl group of the 2'-carbon is replaced with a hydrogen atom.