How does one refer to the amino acids in a peptide?

Once a part of a peptide an amino acid is no longer an amino acid, so how do we refer to the part of the peptide that was once amino acid x?




A part of the peptide that was previously an amino acid molecule when free can be correctly referred to as an amino acid *residue* when bound in the peptide.


[A source](https://study.com/academy/lesson/what-is-amino-acid-residue.html)


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