What is the Difference Between Post Transcriptional and Post Translational Modification?

The main difference between post-transcriptional and post-translational modification lies in the stage of the protein synthesis process at which they occur.

• Post-transcriptional modification: These modifications occur after the transcription step of the protein synthesis process, while the RNA transcript is still in the form of precursor mRNA. Examples of post-transcriptional modifications include the addition of the 5' cap, poly A tail, and splicing. These modifications can lead to the creation of different protein isoforms through alternative splicing.
• Post-translational modification: These modifications occur after the translation step of the protein synthesis process, when the mRNA molecule has been converted into an immature protein. Post-translational modifications can include processes such as ubiquitination and sumoylation, which regulate the activity of preexisting molecules. These modifications usually deal with the activation or inactivation of proteins or enhance their function.

In summary, post-transcriptional modifications are made to the RNA transcript before it is translated into a protein, while post-translational modifications are made to the protein after it has been synthesized.

Comparative Table: Post Transcriptional vs Post Translational Modification

The key difference between post-transcriptional and post-translational modifications lies in the stage of protein synthesis at which they occur. Here is a table comparing the two types of modifications:

Post-transcriptional modifications include the addition of a 5' cap, poly A tail, and splicing, which can lead to the generation of different isoforms of the same protein. On the other hand, post-translational modifications occur in the endoplasmic reticulum/Golgi apparatus and involve modifications to the protein after translation, such as activation/inactivation or enhancing the protein's function.