Termination occurs when one of the three termination codons
moves into the A site. These codons are not recognized by any tRNAs. Instead, they are recognized by proteins called release factors, namely RF1 (recognizing the UAA and UAG stop codons) or RF2 (recognizing the UAA and UGA stop codons). These factors trigger the hydrolysis of the ester bond in peptidyl-tRNA and the release of the newly synthesized protein from the ribosome. A third release factor RF-3 catalyzes the release of RF-1 and RF-2 at the end of the termination process.