Peptidyl Site (P site)

Definition

The peptidyl site, or P site, is the location on the ribosome where the growing polypeptide chain is held during protein synthesis.

Related terms

Aminoacyl Site (A site):

This is where each new tRNA molecule carrying an amino acid attaches to the ribosome during protein synthesis.

Exit Site (E site): This is where discharged tRNAs leave the ribosome after they have delivered their amino acid.

Polypeptide Chain:

A long chain of amino acids linked by peptide bonds that forms part of a protein's structure.