Uric acid

Your body makes a thing called uric acid.

It is a normal part of your pee. Most of it leaves your body through your kidneys.

This acid helps keep your blood healthy. It works like a shield to stop damage.

Sometimes, you might have too much of it. This can make your joints hurt. It can even make small stones in your kidneys.

Eating certain foods can change your levels. Meat and fish can make levels go up.

Drinking water is a good way to stay healthy.

Uric acid is a natural part of your body. It is made when your body breaks down parts called purines.

In humans, uric acid helps protect us. It acts as an antioxidant. An antioxidant is something that stops damage in the body. In fact, over half of the antioxidant power in your blood comes from it.

Most uric acid leaves the body through urine. The kidneys do about 70% of this work. However, some animals use it differently. Birds and reptiles get rid of it in their waste. This helps them save water so they do not get too dry.

Sometimes, people have too much uric acid in their blood. This is called hyperuricemia. Too much can cause gout. Gout is a painful condition. It happens when uric acid forms sharp crystals in your joints.

Eating certain foods can change your levels. Meat and some fish have many purines. Eating too much of these can raise your levels. High levels can also lead to kidney stones. These are hard stones that form in the kidneys.

Uric acid is a natural substance found in the bodies of many living things. It is made of carbon, nitrogen, oxygen, and hydrogen. This substance is a product of how the body breaks down parts called purine nucleotides. In humans, uric acid is a normal part of urine. It can also form salts known as urates. While it is very common, having too much in the blood can lead to medical problems. High levels are linked to conditions like diabetes or the formation of kidney stones.

Inside the body, a specific process creates uric acid. An enzyme called xanthine oxidase helps this happen. This enzyme works by turning xanthine and hypoxanthine into uric acid. The enzyme is quite large and uses a metal called molybdenum to do its job.

This process is part of how the body manages energy and waste. In some cases, eating too much fructose can also increase these levels. This happens because the body uses a pathway that turns fructose into other substances, which eventually become uric acid.

Scientists have studied uric acid for a long time. A Swedish chemist named Carl Wilhelm Scheele first isolated it in 1776. He found it inside kidney stones. Later, in 1882, a Ukrainian chemist named Ivan Horbaczewski found a way to make it. He did this by melting urea with glycine. This helped researchers understand the chemical structure of the substance much better.

Uric acid behaves in many different ways depending on the environment. It does not dissolve very easily in water. For example, it takes 15,000 grams of cold water to dissolve just one gram of uric acid. However, it dissolves much better in hot water.

In humans, the kidneys are responsible for removing about 70% of the uric acid every day. A normal amount of uric acid in the urine is between 270 and 360 mg per day.

This substance is very important for how different animals survive. In humans, uric acid acts as a strong antioxidant. This means it helps protect our blood from damage. Most other mammals have an enzyme that turns uric acid into something else called allantoin. But birds and reptiles do things differently. They excrete uric acid in their waste as a dry mass.

This clever way of working helps them save water and prevents them from getting too dry.

Uric acid is a complex chemical compound made of carbon, nitrogen, oxygen, and hydrogen. Its chemical formula is C5H4N4O3. This substance is a natural byproduct of the body breaking down purine nucleotides. In the human body, it usually exists as the urate ion, which is a conjugate base.

Uric acid is vital because it acts as a powerful antioxidant. In human blood plasma, more than half of the antioxidant capacity comes from the hydrogen urate ion. This helps protect cells from damage. However, if levels in the blood become too high, it can lead to medical issues like gout or kidney stones.

The production of uric acid follows a specific biological pathway. It begins with the breakdown of purines into substances called hypoxanthine and xanthine. An enzyme called xanthine oxidase (XO) then catalyzes the conversion of these substances into uric acid.

This enzyme is quite large and contains a metal called molybdenum bound to sulfur and oxygen. While its name suggests it acts as an oxidase, it mostly functions as a dehydrogenase. In some cases, diet can change this process. For example, consuming excessive fructose can trigger an unregulated pathway. This pathway consumes ATP and converts fructose into fructose-1-phosphate, which eventually leads to the degradation of AMP into uric acid.

Uric acid behaves differently depending on the species of animal. In most mammals, an enzyme called uricase further breaks down uric acid into a substance called allantoin. Humans and other higher primates have lost this uricase enzyme. Because of this, uric acid is the final breakdown product of purine metabolism in humans. Some scientists believe that in primates, urate may partially substitute for vitamin C, which is also a strong antioxidant. Other animals use uric acid for different survival needs. Birds, reptiles, and some desert mammals, like the kangaroo rat, excrete uric acid as a dry mass in their feces. This process is energetically expensive, but it prevents dehydration by reducing water loss.

Even different breeds of animals show unique genetic traits regarding this compound. For instance, Dalmatian dogs have a genetic defect in how their liver and kidneys take up uric acid. This defect prevents them from converting it to allantoin, so they excrete uric acid instead. In the world of invertebrates, the marine worm *Platynereis dumerilii* uses uric acid for communication. The female releases the acid into the water as a sexual pheromone. This chemical signal induces males to release sperm, helping the species reproduce.

History shows how much we have learned about this molecule. In 1776, a Swedish chemist named Carl Wilhelm Scheele first isolated uric acid from kidney stones. This was a major step in understanding metabolic waste. Later, in 1882, Ukrainian chemist Ivan Horbaczewski successfully synthesized the compound. He achieved this by melting urea with glycine. These discoveries allowed scientists to study the chemical structure and the way it crystallizes in the lactam form.

Understanding the solubility of uric acid is crucial for medicine. Generally, uric acid and its salts have low water solubility. This low solubility is a key factor in the development of gout. For example, it takes 15,000 grams of cold water to dissolve just one gram of uric acid. However, it is much more soluble in hot water.

In humans, the kidneys handle about 70% of daily uric acid disposal. A normal daily excretion in urine is between 270 and 360 mg. If the kidneys do not excrete it properly, a person may develop hyperuricemia, which means high levels of uric acid in the blood.

High levels of uric acid can cause serious health conditions. Gout is a painful condition where monosodium urate crystals form in joints and tissues. These crystals are often described as needle-like.

Another serious concern is Tumor Lysis Syndrome. This occurs when cancer cells break down rapidly, releasing their contents into the blood. This can cause uric acid levels to spike, potentially leading to acute kidney injury. Doctors treat these high levels using methods like hyperhydration or medicines like allopurinol, which inhibits the enzyme xanthine oxidase to slow down production.