Purine

Purine is a nitrogen-containing aromatic heterocycle composed of fused imidazole and pyrimidine rings. Its derivatives include the nucleobases adenine and guanine.

Imidazole: Imidazole is a five-membered aromatic ring containing two nitrogen atoms. One of purine’s two fused rings is an imidazole ring.
Purine biosynthesis: Purine biosynthesis is the cellular production of purine nucleotides from smaller precursors. This pathway assembles the purine ring directly on a sugar-phosphate scaffold.
Caffeine: Caffeine is a naturally occurring purine alkaloid that stimulates the central nervous system. Its purine-derived structure connects a familiar stimulant to this chemical family.
Pyrimidine nucleobase: A pyrimidine nucleobase is a single-ring base, including cytosine, thymine, and uracil. Pyrimidine bases contrast with purine bases, which have two fused rings.
Pyrimidine: Pyrimidine is a six-membered aromatic ring containing two nitrogen atoms. Purine’s second fused ring has the pyrimidine structure.
Purine salvage pathway: The purine salvage pathway recycles free purine bases into nucleotides. Salvage reuses purine bases and reduces the need for de novo synthesis.
Theobromine: Theobromine is a purine alkaloid found especially in cacao and chocolate. It is another dietary purine derivative, distinct from caffeine in its effects.
Pteridine: Pteridine is a fused bicyclic heterocycle composed of pyrimidine and pyrazine rings. It is a related nitrogen-rich fused ring system with a different ring arrangement.
Adenine: Adenine is a purine nucleobase found in DNA, RNA, and many cellular molecules. Adenine is one of the best-known biological derivatives of purine.
Purine catabolism: Purine catabolism is the enzymatic breakdown of purines into smaller products. It describes what happens to purine compounds after cellular use and turnover.

Linked from 27 pages