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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 .
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 ( PRPP ) by ribose-phosphate diphosphokinase , which is activated by inorganic phosphate and inactivated by purine ribonucleotides.
The purine nitrogenous bases are characterized by their single amino group (−NH 2), at the C6 carbon in adenine and C2 in guanine. [5] Similarly, the simple-ring structure of cytosine, uracil, and thymine is derived of pyrimidine, so those three bases are called the pyrimidine bases. [6]
A nucleoside consists simply of a nucleobase (also termed a nitrogenous base) and a five-carbon sugar (ribose or 2'-deoxyribose) whereas a nucleotide is composed of a nucleobase, a five-carbon sugar, and one or more phosphate groups. In a nucleoside, the anomeric carbon is linked through a glycosidic bond to the N9 of a purine or the N1 of a ...
In living organisms, the most common bases for ribonucleotides are adenine (A), guanine (G), cytosine (C), or uracil (U). The nitrogenous bases are classified into two parent compounds, purine and pyrimidine. General Ribonucleotide Structure: phosphate group, Ribose, Nucleobase.
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.
The secondary structure is responsible for the shape that the nucleic acid assumes. The bases in the DNA are classified as purines and pyrimidines. The purines are adenine and guanine. Purines consist of a double ring structure, a six-membered and a five-membered ring containing nitrogen. The pyrimidines are cytosine and thymine. It has a ...
Phosphagen system (ATP-PCr) and purine nucleotide cycle (PNC) [1] The Purine Nucleotide Cycle is a metabolic pathway in protein metabolism requiring the amino acids aspartate and glutamate. The cycle is used to regulate the levels of adenine nucleotides, in which ammonia and fumarate are generated. [2] AMP converts into IMP and the byproduct ...