Enzyme responsible for recognition of the amino acids corresponding to specific messenger RNA codons.

Aminoacyl tRNA synthetases recognize specific tRNAs and specific amino acids, covalently bonding the amino acid to the tRNA. The result is a so-called charged tRNA or aminoacyl tRNA.

It is aminoacyl tRNAs that enter the A site of ribosome to deliver amino acids, one amino acid at a time, to growing polypeptide chains.

The core components of the (rRNAs, , and ) have highly conserved sequences across all domains of life, hence the use of sequences for inferring the . Aminoacyl-trNA synthetases (aaRSs) the formation of aminoacyl-tRNAs and are therefore essential for the translation process. However, unlike the core components that must work cooperatively in very precise ways, individual aaRSs interact with only a small subset of the tRNAs and essentially function in isolation in the cell. mirroring the on these different parts of the translation apparatus, the core components produce a common universal tree of life showing the accepted view of the three domains, whereas aRRSs tend to show a different topology consistent with (LGT), including possible transfer from (this quote is from )

There is at least one type of aminoacyl tRNA synthetase in a cell for every translated amino acid.