Threonine

Our bodies need special bits to build proteins.

These bits are called threonine. Our bodies cannot make them on our own. This means we must get them from food.

You can find them in fish or meat. Lentils and beans also have them. Some seeds like sesame have them too. Eating these foods helps our bodies grow. It is a very important part of eating well.

Threonine is an amino acid. Amino acids are the small parts that build proteins.

This part is essential for humans. This means our bodies cannot make it. We must get it from the food we eat. You can find it in fish, meat, and poultry. It is also in lentils, beans, and sesame seeds.

Scientists discovered threonine in 1935. William Cumming Rose and Curtis Meyer found it. It was the last of the 20 common amino acids to be found.

Plants and tiny germs like E. coli can make it. They make it from a different part called aspartate.

Threonine can change in different ways inside a body. It can join with other parts to make new things. In some animals, it turns into a substance called pyruvate. In humans, it turns into something called alpha-ketobutyrate. This helps the body use the amino acid. Some studies look at how threonine might help fight sickness. For example, it might help researchers find new ways to treat tuberculosis.

Threonine comes in different shapes. These shapes are called stereoisomers. Most people just use the name L-threonine.

Threonine is a special kind of amino acid. Amino acids are the building blocks used to make proteins.

This specific amino acid is essential for humans. This means our bodies cannot make it on our own. We must get it by eating certain foods. You can find it in fish, meat, and poultry. It is also in lentils, black turtle beans, and sesame seeds.

Plants and tiny germs like E. coli can make threonine. They use a process called biosynthesis to build it. In these living things, threonine starts from a part called aspartate. It moves through steps involving things called homoserine and homoserine kinase.

These steps use special tools called enzymes. One enzyme used is called threonine synthase. This way of working allows plants to grow and thrive.

Scientists discovered threonine in 1935. A man named William Cumming Rose found it. He worked together with a partner named Curtis Meyer. It was actually the very last of the 20 common amino acids to be discovered.

The name comes from its similarity to threonic acid. Threonic acid is a simple sugar with four carbons. This discovery helped us understand how proteins are built.

Threonine can change its shape or form inside a body. These different shapes are called stereoisomers. There are four possible shapes for threonine.

One shape is called L-threonine. Another rare shape is called L-allothreonine. Threonine can also undergo a change called phosphorylation. This is when a part called a phosphate group is added. This change can help the amino acid work in different ways.

Understanding threonine helps us learn about health and history. In human evolution, a change helped our bodies use threonine better. This change helped support higher metabolic rates and bone growth.

Scientists also study it to fight sickness. They are looking at how it might help treat tuberculosis. This is a serious infection that affects many people. By studying these tiny building blocks, we learn how to stay healthy.

Threonine is a vital amino acid used in the biosynthesis of proteins. Amino acids are the small molecules that build the proteins in every living thing.

Threonine is a polar, uncharged amino acid. This means it has a specific electrical charge that helps it interact with water. It contains an α-amino group and a carboxyl group. It also has a side chain with a hydroxyl group. Because it is polar, it often forms hydrogen bonds with other molecules. These bonds help create small motifs like ST turns or ST staples. These structures are very important for the shape of alpha helices in proteins.

In humans, threonine is considered an essential amino acid. This means the human body cannot synthesize it on its own. We must obtain it through our diet to stay healthy. Adult humans generally require about 20 mg per kilogram of body weight every day. You can find threonine in many common foods. Some good sources include poultry, fish, and meat. It is also found in lentils, black turtle beans, and sesame seeds. Cottage cheese is another food that contains this important building block.

While humans cannot make it, plants and microorganisms can. For example, the bacterium E. coli can synthesize threonine from aspartate. This process involves several specific steps and enzymes. First, aspartate is converted through a pathway involving α-aspartyl-semialdehyde and homoserine.

The enzyme homoserine kinase plays a key role here. Homoserine undergoes O-phosphorylation to continue the process. Finally, threonine synthase helps complete the creation of the amino acid. This complex chain of chemical reactions allows bacteria to build the proteins they need to live.

Threonine is unique because it has two stereogenic centers. This allows the molecule to exist in four different possible stereoisomers. These are different spatial arrangements of the same atoms. The four configurations are (2S,3R), (2R,3S), (2S,3S), and (2R,3R).

The most common form used in nature is L-threonine, which is the (2S,3R) version. Another version, called L-allothreonine, has the (2S,3S) configuration. This specific shape is rarely found in nature. Understanding these different shapes is a major part of studying molecular biology.

Scientists discovered threonine in 1935. It was discovered by William Cumming Rose, who worked with Curtis Meyer. Interestingly, threonine was the very last of the 20 common proteinogenic amino acids to be found. The name was chosen because the molecule is similar to threonic acid. Threonic acid is a four-carbon monosaccharide. This discovery helped complete our map of how life builds itself at a microscopic level.

Threonine can also change through posttranslational modifications. This means the molecule is altered after the protein is already made. For example, the hydroxyl side-chain can undergo O-linked glycosylation. It can also undergo phosphorylation through the action of a threonine kinase. When this happens, the molecule is called phosphothreonine. This new form has three potential coordination sites. These sites allow it to interact with metal ions in biological processes. These changes are how cells signal and control different functions.

Evolutionary history shows that threonine played a role in human development. A specific regulatory variant helped increase the expression of an enzyme called ACSF3. This enzyme is involved in threonine catabolism, or how the body breaks it down. This genetic change is not found in non-human great apes. It likely helped humans support higher basal metabolic rates. It may have also promoted skeletal growth. This suggests that our diet and our metabolism evolved together over a long time.

Today, researchers study threonine to solve modern medical problems. Scientists are looking at how it might help treat tuberculosis (TB). TB is a serious airborne infection that killed 1.25 million people in 2023. Some studies show that threonine can inhibit a specific pathway in E. coli. Researchers hope to apply these findings to help find new drug targets for TB. Additionally, threonine is studied in animal health. It is important for the metabolism of fats and the health of the intestines in animals like broilers.