Adenosine triphosphate

Adenosine triphosphate, or ATP, is a very important chemical found in all living things. It helps give energy to cells so they can do their jobs, like moving muscles and sending messages.

When cells need energy, ATP changes into smaller molecules called adenosine diphosphate or adenosine monophosphate. Later, it is made again so it can be used some more.

ATP is also a building block for DNA and RNA, the molecules that carry instructions for life.

From a chemistry point of view, ATP is made of three parts: a base called adenine, a sugar called ribose, and three phosphate groups. This helps ATP store and release energy exactly where and when a cell needs it.

Structure

ATP has three parts: a sugar, a special base called adenine, and three phosphates linked together. The adenine connects to the sugar, and the sugar holds the three phosphates. In the body, ATP can lose one or two phosphates, becoming ADP or AMP.

ATP can also bind to metals, especially magnesium. This helps ATP work with proteins in the cell and is important for many of ATP’s functions.

Chemical properties

ATP can be found as colorless solids. It stays stable in water when the pH level is between 6.8 and 7.4, but breaks down quickly at more extreme pH levels. In living cells, there is much more ATP than a similar energy molecule called ADP, which helps cells do important work.

Reactive aspects

When ATP breaks down, it releases energy that cells can use to do work. This is very important for all living things. The amount of energy released depends on what is inside the cell and can change a little.

Some minerals, like magnesium, can change how much energy is released when ATP breaks down. This shows how the chemistry of life is connected to tiny details of how molecules work together.

Main article: Standard state

Production from AMP and ADP

Production, aerobic conditions

In our bodies, a typical amount of ATP is between 1–10 micromoles per gram of muscle tissue. ATP can be made in several ways, but three main paths in cells with a nucleus are: (1) glycolysis, (2) the citric acid cycle/oxidative phosphorylation, and (3) beta-oxidation. When we break down glucose completely, we can make about 30 ATP molecules from each glucose.

Most ATP in cells that need oxygen is made in the mitochondria, tiny parts inside cells that help turn food into energy.

Glycolysis

In glycolysis, glucose is turned into a simpler molecule called pyruvate. This process makes two ATP molecules and also creates two molecules of NADH, which can help make more ATP later.

Glycolysis has two parts. In the first part, we spend one ATP to get ready, and in the second part, we make two ATP molecules back. Overall, we make a net of two ATP molecules.

Citric acid cycle

In the mitochondrion, pyruvate is changed into a two-carbon piece that goes through the citric acid cycle. Each turn of this cycle makes energy carriers like NADH and FADH₂, which help make more ATP.

Beta oxidation

When we break down fats, each cycle makes one NADH and one FADH₂, which help make ATP through the citric acid cycle and oxidative phosphorylation.

Ketosis

When we don’t have enough glucose, our body can use ketone bodies for energy, making ATP in the mitochondria.

Production, anaerobic conditions

When there’s no oxygen, cells can still make ATP through fermentation. For example, breaking down glucose can make ATP and lactic acid.

ATP production during photosynthesis

In plants, ATP is made in the chloroplast using light energy in a process called photophosphorylation.

ATP recycling

Our bodies recycle ATP many times each day. The total amount of ATP in our bodies stays about the same, but each ATP molecule is used and recycled around 1000–1500 times daily.

Biochemical functions

ATP is like energy money for cells. When cells need energy, ATP can lose one of its parts to become ADP, releasing energy to power important jobs like moving muscles or sending signals in the brain.

ATP also helps cells talk to each other and build important molecules like DNA and RNA. It even helps muscles contract by giving energy to proteins that pull on each other to make movement possible.

Abiogenic origins

Scientists have found ways to make a molecule called acetyl phosphate. This molecule helps create ATP, the energy carrier in our cells. They can make it from another chemical called thioacetate under normal air temperature and slightly basic water. Acetyl phosphate doesn’t last as long when it gets warmer or more alkaline. It can help gather and stabilize another molecule called AMP. It might also help link smaller molecules together, especially on surfaces of minerals. Importantly, acetyl phosphate can turn ADP into ATP. This could be why all living things use ATP for their energy needs.

ATP analogues

Scientists use special versions of ATP, called ATP analogs, to study how cells use energy. These analogs help researchers see how proteins work with ATP. One common analog replaces an oxygen atom in ATP with a sulfur atom. This makes it harder for enzymes to break it down. This helps scientists learn more about how cells use energy. Scientists need to be careful when using these analogs because some enzymes might still break them down sometimes.

Medical use

ATP can be put into the bloodstream to help treat some heart problems. Doctors use this to quickly support the heart’s health and how well it works.

History

ATP was discovered in 1929 by Karl Lohmann and also by Cyrus Fiske and Yellapragada Subba Rao. They were studying muscle tissue. In 1941, Fritz Albert Lipmann said that ATP helps move energy inside cells.

In 1948, Alexander Todd made ATP in a lab. He won a Nobel Prize in Chemistry in 1957 for this work. Other scientists also won Nobel Prizes for learning more about ATP and how it works in our cells. These scientists include Peter Dennis Mitchell, Paul D. Boyer, John E. Walker, and Jens C. Skou.