peptide modification

Definition

Target type: biologicalprocess

The covalent alteration of one or more amino acid residues within a peptide, resulting in a change in the properties of that peptide. [GOC:mah]

Peptide modification is a fundamental process in biology that alters the structure, function, and fate of peptides and proteins. This process involves the covalent attachment of various chemical groups to amino acid residues within a peptide chain. These modifications can occur during or after protein synthesis and play crucial roles in regulating a wide range of cellular processes, including protein folding, stability, activity, localization, and interaction with other molecules.

There are numerous types of peptide modifications, each with specific consequences for the modified peptide. Some common examples include:

* **Phosphorylation:** The addition of a phosphate group to a serine, threonine, or tyrosine residue. Phosphorylation is a major regulatory mechanism in signaling pathways, enzyme activity, and protein-protein interactions.

* **Glycosylation:** The attachment of sugar molecules to asparagine, serine, or threonine residues. Glycosylation is essential for protein folding, stability, and recognition by other molecules. It plays a role in immune response, cell adhesion, and signal transduction.

* **Acetylation:** The addition of an acetyl group to the N-terminal amino acid of a peptide. Acetylation can affect protein stability, localization, and interactions with other proteins. It is also involved in gene regulation.

* **Ubiquitination:** The attachment of a ubiquitin molecule to lysine residues. Ubiquitination is a key mechanism for protein degradation and signaling. It is involved in various cellular processes, including cell cycle control and DNA repair.

* **Methylation:** The addition of a methyl group to lysine or arginine residues. Methylation can alter protein activity, stability, and interactions. It plays a role in gene regulation, DNA replication, and cell signaling.

* **Sumoylation:** The attachment of a small ubiquitin-like modifier (SUMO) protein to lysine residues. Sumoylation can affect protein stability, localization, and interactions. It is involved in various cellular processes, including transcription, DNA repair, and nuclear transport.

Peptide modifications are highly dynamic and regulated processes. Enzymes called kinases, glycosyltransferases, acetylases, ubiquitin ligases, methyltransferases, and SUMO ligases are responsible for adding modifications, while phosphatases, glycosidases, deacetylases, deubiquitinases, demethylases, and SUMO proteases remove them. The balance between these opposing activities is critical for maintaining proper cellular function.

Understanding the mechanisms and consequences of peptide modifications is essential for comprehending the complexity of cellular processes and developing new therapeutic strategies for diseases caused by dysregulation of these modifications.'
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Proteins (1)

Compounds (1)