Uric acid serves as an antioxidant in the blood. This is true only for man and some of the great apes. Most animals have the capacity to produce their own vitamin C which circulates in their blood and provides the antioxidant protection they need. Our bodies can't produce vitamin c but we do get it from our food. This vitamin c (ascorbate) circulates in our blood adding to the antioxidant protection that uric acid provides. This double protects helps, in part, to explaining our longer life span than many animals. The uric acid also combines with free floating iron to form a complex that potects the ascorbate. These uric acid-iron complexes are very important in the formation of the monosium urate crystals that are central to gout.
The body needs iron but in its free form it is toxic to the body. Iron is unique among the minerals in that it acts as an electron donor and receptor. It is very capable of harming the body's cells as it gives up and takes ions. While the body desperately needs the right amount of iron, it also needs to protect its cells from the harm done by free floating iron. The body works very hard to do this. Under normal circumstances, only one percent of the iron in your body is free floating. However, under some circumstances, that percentage can go up leading to gout.
The body protects itself with different protein structures (red blood cells, transferrin, ferritin, etc). Once stored in the structures, the iron doesn't harm the body's cells. Instead, it serves a number of useful functions. The problem is that these structures can only hold so much iron. Eventually, they become saturated. The more saturated, the less iron the body needs to take in in its diet.
The body has a protective mechanism in its intestinal lining that controls how much iron is allowed to enter the body from the food that is being digested in the intestines. The more saturated the body is with iron, the less iron is allowed to pass through the intestinal lining. The less saturated the body is, the more iron is allowed to pass through. The system works well, except that if the food contains certain substances (fructose, alcohol, etc) more iron will get through than the body needs. The result is too much free floating iron which is to toxic to the body.
The protective mechanism in the intestinal lining is the first line of defense to too much free floating iron. The protein structures are the second line of defense. The uric acid-iron complexes may be the body's third line of defense. This is in an idea that was put forward by a research team of Ghio, Ford, Kennedy, & Hoidal. I believe they are right!
Consider this idea. The body is being confronted by too much free-floating, toxic iron which has made it past its first line of defense, the intestinal lining. The toxic iron is in its blood stream and is damaging its cells. Normally, it would store the iron in the protein structures, the second line of defense, but these are saturated. Its only remaining option is to generate a massive amount of uric acid. This uric acid would then unite with the free floating iron to form the uric acid-iron complexes. These complexes minimize the harm the iron does but doesn't stop it entirely. In a sense, the iron is stored as in the case of the protein structures but not as well. (Its an imperfect world and the body is making the best of a bad situation.) The uric acid is being generated by the body to deal with this free floating iron as a kind of stop gap measure.
This is where the work of the research team ended. Basically their work and that of others have proven that iron is very much a major factor in generating the uric acid. It is also involved in the inflammation process.