peptidyltransferase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: peptidyl-tRNA(1) + aminoacyl-tRNA(2) = tRNA(1) + peptidylaminoacyl-tRNA(2). This reaction is catalyzed by a ribozyme. [PMID:11433365, PMID:9242921]

Peptidyltransferase activity is a fundamental enzymatic function essential for protein synthesis. It catalyzes the formation of peptide bonds between amino acids, linking them together in a specific sequence dictated by the messenger RNA (mRNA). This process occurs within the ribosome, the cellular machinery responsible for protein translation. The active site of peptidyltransferase is located within the large ribosomal subunit, specifically within the peptidyl transferase center (PTC). The PTC is composed of ribosomal RNA (rRNA) molecules and ribosomal proteins, forming a highly conserved catalytic site. During protein synthesis, the tRNA carrying the growing polypeptide chain (peptidyl-tRNA) occupies the P site of the ribosome, while the tRNA carrying the next amino acid to be added (aminoacyl-tRNA) occupies the A site. Peptidyltransferase activity is responsible for the transfer of the polypeptide chain from the P-site tRNA to the amino acid attached to the A-site tRNA. This reaction involves the nucleophilic attack of the amino group of the A-site amino acid on the carbonyl group of the peptidyl-tRNA, resulting in the formation of a new peptide bond. The released tRNA from the P-site then exits the ribosome, and the ribosome shifts to the next codon on the mRNA, ready for the addition of the next amino acid. Peptidyltransferase activity is crucial for the accurate and efficient synthesis of proteins, which play vital roles in all cellular processes.'
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Proteins (1)

Compounds (1)