Purine
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Image:Adenine.png
Adenine
(6-amino purine)
Image:Guanine.png
Guanine
(2-amino, 6-oxy purine)
Purines are one of two categories of organic base found in nucleic acids. The other category is the pyrimidines. The purines found in nucleic acids are adenine and guanine, though there are other purines used elsewhere in the body. Purines are larger molecules than pyrimidines, containing both six and five member nitrogen/carbon rings. Because purines and pyrimidines are different sizes purines always pair with pyrimidines in nucleic acids:
This is known as the Watson-Crick base pairing
When a pentose sugar is added to the purines, forming nucleosides they are names adenosine and guanosine. A phosphate group can be added to these to produce a nucleotide, the monomer in nucleic acids.
There are two other purines found in organisms that aren't part of nucleic acids:
- Hypoxanthine (6-oxy purine)
- Xanthine (2,6-dioxy purine)
Purine catabolism produces uric acid, a component of urine.
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This page is part of the EvoWiki encyclopedia of genetics and molecular biology. Topics: Genetics - Transmission genetics - Molecular genetics - Population genetics - Quantitative genetics - Molecular biology - Genomics |
