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The Peptidyl transferase is an aminoacyltransferase () as well as the primary enzymatic function of the ribosome, which forms peptide bonds between adjacent amino acids using tRNAs during the translation process of protein biosynthesis. Peptidyl transferase activity is carried out by the ribosome. Peptidyl transferase activity is not mediated by any ribosomal proteins but by ribosomal RNA (rRNA), a ribozyme. Ribozymes are the only enzymes which are not made up of proteins, but ribonucleotides. All other enzymes are made up of proteins. This RNA relic is the most significant piece of evidence supporting the RNA World hypothesis. * In Prokaryotes, the 50S (23S component) ribosome subunit contains the peptidyl transferase component and acts as a ribozyme. * In Eukaryotes, the 60S (28S component) ribosome subunit contains the peptidyl transferase component and acts as the ribozyme. Peptidyl transferases are not limited to translation, but there are relatively few enzymes with this function. ==Antibiotic target== The following protein synthesis inhibitors target peptidyl transferase: *Chloramphenicol binds to A2451 and A2452 residues in the 23S rRNA of the ribosome and inhibits peptide bond formation. *Pleuromutilins also bind to peptidyl transferase. *Macrolide antibiotics are thought to inhibit peptidyl transferase, in addition to inhibiting ribosomal translocation.〔(Protein synthesis inhibitors: macrolides mechanism of action animation. Classification of agents ) Pharmamotion. Author: Gary Kaiser. The Community College of Baltimore County. Retrieved on July 31, 2009〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Peptidyl transferase」の詳細全文を読む スポンサード リンク
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