which amino acids can be phosphorylated?

which amino acids can be phosphorylated

In this article, we will try our best to answer the question of which amino acids can be phosphorylated? It is a complicated question, and the answer is also complicated and difficult to understand if you are new to the world of protein and amino acid phosphorylation.

What are Amino acids?

An amino acid is an organic compound and is one of the building blocks of proteins. There is a carboxyl group, an amino group, and a side chain that consists of an acid or alcohol. The carboxyl group and amino group give them the ability to act both as acids and bases. As a result of this carboxyl or amino structure, these molecules can recombine with other molecules to form new structures, such as peptides and proteins. Various amino acids can be described based on their chemistry or physical properties, such as their solubility in water or their ability to form stable complexes with other molecules.

An amino acid is a natural organic compound, which is the building block of proteins. The human body uses 20 amino acids for various purposes, including energy production and repair.

There are four categories of amino acids: non-essential, essential, conditionally essential, and pseudo-essential. Unlike essential amino acids, non-essential amino acids can be synthesized in the body and are therefore not required to be consumed. Humans cannot synthesize essential amino acids and must obtain them from food. Conditionally essential amino acids can either be synthesized by the body; however, during stress or disease, they become depleted, or the body cannot make enough. Lastly, pseudo-essentials are amino acids that may still have beneficial effects on health even if they are not essential.

What is Phosphorylation?

Phosphorylation is the addition of phosphate to an organic molecule. The phosphorylation process can occur in reverse, and this process is called dephosphorylation. Dephosphorylation is the removal of phosphate. Enzymes such as kinases and phosphotransferases execute both phosphorylation and dephosphorylation. Phosphorylation is crucial for the proper function of proteins and enzymes, sugar metabolism, and energy storage and release.

Phosphorylation plays an essential role in regulating processes in the body through phosphorylation and dephosphorylation cycles. These phosphorylation and dephosphorylation cycles allow the body to control various functions, such as cell movement, reproduction, and metabolism. The simplicity, speed and reversibility of these processes are why the body has evolved to utilize phosphorylation widely.[1]

Phosphorylation of Serine
Phosphorylation of Serine

What is Protein phosphorylation?

Early in the 19th century, it was discovered that phosphates were linked to proteins. Scientists simply viewed these phosphoproteins as a biological method of providing phosphorus as a nutrient. Phosphoproteins were thought to exist only due to metabolic reactions for nearly a century after their discovery.

It was not until the 1950s that phosphoproteins became important as essential regulators of cellular life. During the 1950s, researchers discovered an enzyme activity that transferred phosphate from one protein to another.

As amino acids are phosphorylated, the phosphoryl group is added to them. Serine is usually the amino acid phosphorylated, though threonine and tyrosine can also be phosphorylated in eukaryotes and histidine in prokaryotes. Esterification occurs when an acidic phosphate group reacts with the hydroxyl group of an amino acid side chain, such as serine, threonine, or tyrosine. A phosphate group is covalently bonded to an amino acid by protein kinase. Eukaryotes and prokaryotes have slightly different mechanisms. [2]

which amino acids can be phosphorylated?

The most commonly phosphorylated amino acids are serine, threonine, tyrosine, and histidine. On average, proteins undergo phosphorylation every 17 amino acids. Serine, threonine, and tyrosine phosphorylation among eukaryotes are the most common. The phosphorylation of histidine occurs both in prokaryotes and plants. Lysine, arginine, glutamic acid, aspartic acid, cysteine, and asparagine are other amino acids that can be phosphorylated post-translationally. Phosphorylation regulates many biological activities, including cell proliferation, apoptosis, and signal transduction pathways. Proteins phosphorylate amino acids to carry signals through the cell and regulate their function.[3]

Summary of which amino acids can be phosphorylated

Hopefully, the role of phosphorylation and amino acid phosphorylation is clearer for you after reading this article. We tried to distill down the key elements that would best answer the question of which amino acids can be phosphorylated? 

The information in this article is not intended to be taken as medical advice.