protein processing

Definition

Target type: biologicalprocess

Any protein maturation process achieved by the cleavage of a peptide bond or bonds within a protein. Protein maturation is the process leading to the attainment of the full functional capacity of a protein. [GOC:curators, GOC:jl, GOC:jsg]

Protein processing is a complex and essential biological process that involves a series of modifications and transformations that a newly synthesized polypeptide undergoes to become a functional protein. It is a highly regulated process that ensures the proper folding, localization, and activity of proteins. Here is a detailed description of the key steps involved in protein processing:

1. **Translation:** The process of protein synthesis begins with the translation of mRNA into a polypeptide chain by ribosomes. The mRNA sequence dictates the order of amino acids in the polypeptide chain.

2. **Folding:** As the polypeptide chain emerges from the ribosome, it begins to fold into a three-dimensional structure. This folding process is guided by interactions between amino acids, such as hydrogen bonds, hydrophobic interactions, and ionic bonds. The final folded structure is crucial for the protein's function.

3. **Post-translational Modifications:** After translation, many proteins undergo a series of post-translational modifications, which include:

* **Glycosylation:** The addition of sugar molecules to the polypeptide chain. Glycosylation can affect protein stability, folding, and cellular localization.
* **Phosphorylation:** The addition of phosphate groups to amino acid residues. Phosphorylation can regulate protein activity and cellular signaling pathways.
* **Acetylation:** The addition of acetyl groups to the N-terminus of the polypeptide chain. Acetylation can affect protein stability and cellular localization.
* **Ubiquitination:** The attachment of ubiquitin molecules to a protein. Ubiquitination can target proteins for degradation by the proteasome.
* **Proteolytic Cleavage:** The removal of specific amino acid sequences from the polypeptide chain. Proteolytic cleavage can activate proteins or generate smaller, functional protein fragments.

4. **Targeting and Localization:** After folding and post-translational modifications, proteins are often targeted to specific cellular compartments, such as the endoplasmic reticulum, Golgi apparatus, mitochondria, or nucleus. This targeting process ensures that proteins are delivered to the correct location where they can perform their function.

5. **Protein Degradation:** Proteins have a finite lifespan and are eventually degraded by cellular machinery, such as the proteasome. Protein degradation removes damaged or misfolded proteins and regulates protein levels in the cell.

Protein processing is a dynamic and essential process that ensures the proper function of proteins in all living organisms. It is tightly regulated by a complex network of enzymes, chaperones, and cellular pathways, ensuring that proteins are synthesized, folded, modified, and degraded in a controlled and efficient manner.'
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Proteins (40)

Compounds (1,090)