Post-translational modification (PTM)
Post-translational modification (PTM) is a vital biological process that involves chemical alterations to proteins after their synthesis. These modifications can significantly influence protein properties, interactions, and functions, playing essential roles in various biological processes such as cellular structure, cell division, DNA modification, nerve degeneration, and cancer formation. Over three hundred distinct types of PTMs have been identified, with many initiated by enzymes that facilitate specific chemical reactions.
Common PTMs include phosphorylation, where a phosphate group is added to regulate protein function, and glycosylation, which involves the addition of carbohydrates crucial for cell membrane formation. Another key modification is the addition of ubiquitin, a small protein that signals for the degradation of other proteins to maintain cellular health. Additionally, proteolysis refers to the cleavage of proteins into smaller peptides or amino acids, often activating previously inactive proteins. Deamidation involves modifying amino acids within proteins, further altering their stability and function. Understanding PTMs is essential in molecular biology, highlighting their importance in the functional complexity of organisms.
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Post-translational modification (PTM)
Post translational modification (PTM) is a biological process related to genetics. It refers to chemical changes to proteins after they have been formed. The properties may change as well as how the proteins interact. PTM is important to other biological processes such as cellular structure, mitosis or cell division, the modification of deoxyribonucleic acid (DNA), the degeneration of nerves, and the formation of cancer. The study of post translational modification is one of the fastest-growing areas of molecular biology. More than three hundred different modifications have been identified.
The genome is the biological code that determines how an organism will look and function. It also includes all the information needed for the organism to repair itself, reproduce, and generally continue to function. This information is encoded in DNA. It is then transferred into ribonucleic acid (RNA). RNA acts as a messenger to transfer the code to a protein, a process called translation that is an essential function in the formation of an organism.
Translation is sometimes seen as the last step in the genetic process of forming an organism. However, a number of other processes are essential to that organism achieving complete functionality. In addition to a genome, the organism has a proteome. This is the total amount of proteins that an organism has or potentially can have. Post translational modifications are one type of process responsible for the changes that create this proteome.
Overview
More than three hundred post translational modifications can affect how proteins are formed. Most of them are triggered by enzymes, which are proteins that help start or regulate a chemical reaction. In PTM, these enzymes recognize specific types of proteins and start different reactions. These reactions fall into several categories.
Some reactions are based on adding a chemical substance to the protein. For example, adding phosphate results in phosphorylation. This is the most common way human cells control protein functions. It is also the main way that signals are transmitted within cells. Researchers have estimated that about one-third of the proteins in the human proteome were created by phosphorylation.
Other PTMs are the result of the addition of complex groups. An example is glycosylation, where a carbohydrate is added. This type of PTM is important to the formation of cell membranes.
The addition of a tiny protein molecule called ubiquitin is important to a PTM that helps with cell maintenance. Ubiquitin deactivates other proteins. This marks them for destruction, helping to clean up cells that have reached the end of their lifespans.
Protein cleavage is another PTM. Through a process called proteolysis, proteins are broken down into amino acids or polypeptides. This triggers proteins that were inactive after translation into active proteins to fulfill their purpose.
The other main class of PTM is deamidation. In this process, an amino acid is either removed or converted into a different amino acid. These modifications change the function, structure, or stability of the protein.
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