MTRF1L is a nuclear-encoded protein that functions as a releasing factor that recognizes termination codons and releases mitochondrial ribosomes from the synthesized protein ( summary by Nozaki et al ., 2008 [ PubMed 18429816 ] ) . [ supplied by OMIM ].
12.
The genetic code has 64 codons of which 3 function as termination codons : there are only 20 amino acids normally present in proteins . ( There are two uncommon amino acids & mdash; selenocysteine and pyrrolysine & mdash; found in a limited number of proteins and encoded by the stop codons & mdash; TGA and TAG respectively . ) The mismatch between the number of codons and amino acids allows several codons to code for a single amino acid-such codons normally differ only at the third codon base position.
