purine

1. (organic chemistry) Any of a class of organic heterocyclic compounds, composed of fused pyrimidine and imidazole rings, that constitute one of the two groups of organic nitrogenous bases (the other being the pyrimidines) and are components of nucleic acids.Examples: "1982, Ray A. Field, Mechanically Deboned Red Meat, C. O. Chichester, George Franklin Stewart, Advances in Food Research, Volume 27, page 67, Clifford et al. (1976) investigated the metabolism of individual purines and found that adenine, and to a lesser extent hypoxanthine, had pronounced effects on blood uric acid levels. The purine content of foods, in particular adenine, would therefore be of immense nutritional significance."; "For example, for purine-pyrimidine and for pyrimidine-purine base steps the presence of purines on opposite strands in successive base pairs sterically restricts the conformations that these base pairs can adopt relative to each other."; "The discovery that certain pyrazolopyrimidine nucleobases and nucleosides, analogs of naturally occurring purines, are toxic to Leishmania, coupled with the obligatory nature of the leishmanial purine salvage pathway, has spawned considerable interest in the purine salvage pathway as a drug target."countableuncountable