Putrescine

Some things have a very bad smell.

This smell comes from tiny bits in nature. It is in plants and animals. It is also in the air.

This smell can come from flesh that is rotting. It can even be part of bad breath.

But these bits help living things too. They help plants grow well. They also help plants stay strong.

Some bits help plants deal with heat. They can even help fruit stay fresh longer.

Nature uses these bits in many ways. It is a busy world!

Putrescine is a colorless solid. It is found in all living things. Many people know it because of its smell. It helps make the bad odor of rotting flesh. It can also be part of bad breath.

In plants, putrescine helps them grow. It helps plants deal with stress. This includes heat or dry weather. It also helps plants fight off fungi and parasites. Some soil fungi help plants make more putrescine. This can help plant roots grow better.

Putrescine is also useful in farming. Farmers can use it on fruits like peaches and pears. It can help fruit stay firm and fresh. It can even help strawberries stay good for 12 days.

Inside the body, putrescine has many jobs. In the brain, it helps make a chemical called GABA. This chemical helps different parts of the brain work. Putrescine also helps make other parts called spermidine and spermine.

Scientists can also make putrescine in factories. They use it to make a type of nylon. This is a strong material called nylon 46. It was first described in 1885 by Ludwig Brieger.

Putrescine is a colorless solid that melts near room temperature. You might know it because of its very strong, unpleasant smell. It is often found in decaying flesh along with another substance called cadaverine. This combination is what creates the foul odor of rotting things. Even though the smell is bad, putrescine is found in all living things. It plays many important roles in the bodies of plants and animals.

In living cells, putrescine is made through special chemical paths. One way starts with a substance called arginine. An enzyme called arginine decarboxylase turns arginine into agmatine. Then, another enzyme called agmatine imino hydroxylase changes it into N-carbamoylputrescine. Finally, this is broken down to create putrescine. There is also a second path that uses ornithine. In this way, an enzyme called ornithine decarboxylase turns ornithine into putrescine.

Scientists first described putrescine in 1885. A physician from Berlin named Ludwig Brieger discovered it. He chose the name from the Latin word "putresco." This word means to become rotten or to decay. Since then, people have learned much more about it. We now know it is a diamine, which is a type of organic compound. It is used in many different ways today.

Putrescine is very useful in farming and industry. In factories, it reacts with adipic acid to make nylon 46. This is a strong material sold under the name Stanyl. Farmers also use it to help plants and fruits. When applied to fruits like peaches or pears, it delays ripening. It can even help strawberries stay fresh for up to 12 days. In plants, it helps them handle stress from heat or drought.

Inside the brain, putrescine helps with important jobs. It can act as a precursor for a chemical called GABA. This chemical is made in many brain areas like the hippocampus and the cerebellum. It helps control how certain neurons in the brain work. In plants, putrescine helps with energy production in parts called mitochondria and chloroplasts. It also helps plants fight off parasites and fungi.

Putrescine is an organic compound with the chemical formula (CH2)4(NH2)2. It is a colorless solid that melts near room temperature. Scientists classify it as a diamine, which is a type of molecule containing two amine groups. While many people recognize it by its foul odor, it is a vital part of life. Putrescine is found in all living organisms. It plays many different roles in the biology of plants, animals, and even humans.

In living cells, putrescine is created through two distinct biological pathways. Both pathways begin with the amino acid arginine. In the first pathway, an enzyme called arginine decarboxylase (ADC) converts arginine into agmatine. Next, an enzyme known as agmatine imino hydroxylase (AIH) transforms agmatine into N-carbamoylputrescine. Finally, this substance is hydrolyzed to produce putrescine. The second pathway is different. In this route, arginine is first converted into ornithine. Then, an enzyme called ornithine decarboxylase (ODC) turns that ornithine into putrescine.

Once it is made, putrescine can be used to build even more complex molecules. It serves as a building block for other polyamines. For example, the enzyme spermidine synthase combines putrescine with S-adenosylmethioninamine to create spermidine. This spermidine can then be combined with another S-adenosylmethioninamine to produce spermine.

This process is a key part of how cells manage their internal chemistry.

Putrescine also plays a significant role in the brain. It can act as a biological precursor for gamma-aminobutyric acid, or GABA. GABA is a chemical that helps regulate the brain. Putrescine can be transformed into GABA through various intermediates, such as N-acetylputrescine and GABAL. These changes are managed by enzymes like diamine oxidase (DAO) and monoamine oxidase B (MAO-B). In 2021, researchers discovered that MAO-B helps synthesize GABA in astrocytes. This happens in several brain areas, including the hippocampus, cerebellum, striatum, cerebral cortex, and the substantia nigra pars compacta. This synthesized GABA then works to inhibit certain dopaminergic neurons.

In the world of plants, putrescine is often the most common polyamine found in tissues. It helps plants manage stress from the environment, such as heat or drought. It can also act as a regulator for proteins on cell surfaces and inside organelles like mitochondria and chloroplasts. For instance, an increase in putrescine can lead to higher ATP production in these parts of the cell. However, it can also act as a developmental inhibitor. In Arabidopsis plants, high levels can cause dwarfism or late flowering. Without enough putrescine, plants may also see an increase in fungal and parasite populations.

Farmers and scientists use putrescine in interesting ways to help agriculture. When applied to fruits like peaches, plums, or pears, it can delay the ripening process. This extends the shelf life of the produce. In one study, a strawberry coating made of putrescine and chitosan helped the fruit stay fresh for up to 12 days. It also helps fruits keep their firmness, taste, and nutrition. In the soil, a fungus called Piriformospora indica can promote putrescine production in tomato and Arabidopsis plants. This helps the plants grow better root structures.

Beyond biology, putrescine has important industrial and historical uses. In factories, it is produced on an industrial scale through the hydrogenation of succinonitrile. It can also react with adipic acid to create nylon 46, a material sold as Stanyl. Historically, the substance was first described in 1885 by Ludwig Brieger. He was a physician from Berlin. He named the compound "putrescine" from the Latin word *putresco*, which means to become rotten or decay. Because it is found in decaying flesh alongside cadaverine, it is often used as a biochemical marker to help determine how long a corpse has been decomposing.