Purines
The building blocks of life and energy. Purines (adenine and guanine) form half of DNA's base pairs and are part of ATP, the energy currency. When purines are broken down, they produce uric acid. Problems with purine metabolism cause gout and other conditions. Diet influences purine load significantly.
Where Purines Are Found
DNA & RNA
Adenine and guanine bases. Every cell contains DNA. Cell turnover releases purines.
ATP
Adenosine triphosphate. Energy molecule. Contains adenine purine.
Organ Meats
Liver, kidney, sweetbreads. Very high in purines. Dense in cells.
Shellfish
Mussels, scallops, sardines. Moderate to high purines.
Beer
Yeast purines. Plus alcohol impairs uric acid excretion. Double problem.
Certain Vegetables
Spinach, asparagus. Moderate purines but may not affect gout risk.
Purine Metabolism
Breakdown Pathway
Purines → Hypoxanthine → Xanthine → Uric acid. Xanthine oxidase catalyzes.
Uric Acid
End product in humans. Other mammals have uricase to break it down further. We don't.
Kidney Excretion
70% excreted via kidneys. Rest through gut. Competition with other molecules.
Salvage Pathway
Body recycles purines when possible. More efficient than making new ones.
Purine-Related Problems
Gout
Uric acid crystals in joints. Extremely painful. Big toe classic. Diet and genetics.
Kidney Stones
Uric acid stones. Form when urine too acidic and concentrated.
Lesch-Nyhan Syndrome
Rare genetic disorder. HPRT enzyme defect. Severe neurological symptoms.
Cardiovascular Risk
High uric acid linked to heart disease, hypertension. Causation debated.