CH 461 Lecture Notes - Lecture 43: Aminoacyl-Trna, Aminoacylation, Start Codon
Document Summary
Fidelity in trna aminoacylation synthesis, atp and the appropriate amino acid form an aminoacyl adenylate intermediate. Inorganic pyrophosphate is released and subsequently broken down to free phosphate by the enzyme inorganic pyrophosphatase. Aminoacylation is a two step process, catalyzed by a set of enzymes known as aminoacyl trna synthetases. Twenty aminoacyl trna synthetases reside in each cell, one per amino acid in the genetic code. In the first step of aminoacyl trna adenylate is a (cid:1688)high energy(cid:1689) intermediate, and in the second step, the transfer of amino. The aminoacyl trna synthetase carries out an editing step to ensure against aminoacyl trnas as the same for making the peptide bond, any trna bearing the a harmful protein. Editing aminoacyl trnas for accuracy is carried out by a second active site on the aminoacyl trna synthetase. This function of the enzyme cleaves the incorrect aminoacyl trna to yield free amino acid and trna.
