| nonsense codon | <molecular biology> The three codons, UAA (known as ochre), UAG (amber) and UGA (opal), that do not code for an amino acid but act as signals for the termination of protein synthesis. Any mutation that causes a base change which produces a nonsense codon results in premature termination of protein synthesis and probably a nonfunctional or nonsense protein. (13 Nov 1997) |
|---|---|
| initiating codon | The trinucleotide AUG (or sometimes GUG) that codes for the first amino acid in protein sequences, formylmethionine; the latter is often removed post-transcriptionally. Synonym: start codon. (05 Mar 2000) |
| initiation codon | The codon 5' AUG in mRNA, at which polypeptide synthesis is started. It is recognised by formylmethionyl tRNA in bacteria and by methionyl tRNA in eukaryotes. (18 Nov 1997) |
| ochre codon | The codon UAA, one of the three that causes termination of protein synthesis. The most frequent termination codon in E. Coli genes. (18 Nov 1997) |
| opal codon | <molecular biology> The codon UGA, one of the three that causes termination of protein synthesis. (18 Nov 1997) |
| umber codon | The termination codon UGA. Synonym: opal codon. (05 Mar 2000) |