Uric acid

November 30, 2020
If you ate too much on Thanksgiving, I might be the cause of the pain in your feet.
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Uric acid is a purine derivative and an oxidative metabolic product of purine nucleotides in humans and other carnivorous animals. It is a weak acid with a pKa of 5.6 and is sparingly soluble in water.

In 1776, Swedish chemist Carl Wilhelm Scheele discovered uric acid in human urine and kidney stones. The same year, his discovery was confirmed by his colleague Torbern B. Bergman. Uric acid is also found in the feces of birds, reptiles, and some mammals.

Ukrainian–Austrian chemist Ivan Horbaczewski reported an early synthesis of uric acid from glycine in 1882. More recently (1962), C. Wayne Bills and co-workers at the University of Colorado (Boulder) serendipitously synthesized uric acid from urea while they were seeking a new route to pyrimidines.

Uric acid is notorious for the excruciating pain it produces in gout  patients. When the acid is present in high concentrations in the blood, its low solubility causes it to precipitate as sharp crystals in and around joints, notably in the feet. Uric acid concentration increases in the body when people consume large amounts of purine-rich foods such as red meat and seafood.

There has been some speculation that the presence of uric acid and its concomitant gout play a role in COVID-19, but this connection would be indirect at most. People with gout tend to have other serious health problems such as obesity, kidney disease, and cardiovascular disease, which uric acid can exacerbate. According to Theodore R. Fields at the Hospital for Special Surgery (New York City), “Gout does not typically affect immune system function.” Adds Shailendra Singh at White River Medical Center (Batesville, AR), “People with gout don’t have a greater risk of getting coronavirus than the general population, but they do have an increased risk of complications if they do get it.”

Uric acid hazard information

Hazard class*Hazard statement
Not a hazardous substance or mixture 

* Globally Harmonized System of Classification and Labeling of Chemicals.

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Uric acid fast facts

CAS Reg. No.69-93-2
1H-Purine-2,6,8(3H)-trione, 7,9-dihydro-
Empirical formulaC5H4N4O3
Molar mass168.11 g/mol
AppearanceWhite crystals or powder
Boiling point310 ºC (dec.)
Water solubility 60 mg/L
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