= Stop codon
{wiki}
In the standard <genetic code>, UAA, UAG and UGA are <stop codons>: they signal termination of <biological translation> rather than an <amino acid> assignment. See https://openstax.org/books/biology-2e/pages/15-1-the-genetic-code[Clark, Douglas and Choi: stop codons].
A <stop codon> supplies no additional <amino acid residue>. In the constructed AUG GCU UUC UGA example, replacing UGA by UAA preserves termination after the same three <amino acid residues>. Replacing UUC by UAA instead terminates after <methionine> and <alanine>. These are consequences of the stated <genetic code>, not measurements of expression efficiency.
At a standard <stop codon>, a <release factor> promotes release of the <polypeptide> from the <ribosome>. Ordinary delivery of an <amino acid> by <transfer RNA> does not supply a “stop <amino acid>”.<Biology 2e by Mary Ann Clark and others>[§15.5, Translation, Elongation, and Termination, paragraph beginning “Termination of translation”: stop codons and release factors]{ref}
Back to article page
