The termination phase of translation begins when a chain- terminating codon of the mRNA (nonsense codon) (either UAA, UAG or UGA) is recognized,thus determining the interaction of the release factors with the ribosome. A single release factor (RF) has been isolated from eukaryotic systems, GTP being required in the termination step (g1). On the other hand three release factors (RF-1, RF-2,and RF-3) have been obtained from bacterial systems; release factor RF-1 is active by itself,whereas the activity of RF-2 is strongly potentiated by RF-3. It is most likely, but not definitively proven, that GTP is required in step (g1) in bacterial systems.
KeywordsHydrolysis Codon Polypeptide Pseudomonas Streptomycin
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