Uric acid

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 pK_a 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.”