note

doc/typst/chapters/a3_fundamentals-in-bottom-up-proteomics.typ

@@ -38,3 +38,12 @@ The bond formed by condensation of two amino acids is an amide bond, also called
 The elongation of the protein is a simple repetition of the condensation reaction shown in @fig_xtpcpp-peptide-bond-formation, granted that the elongation #emph[always] proceeds in the described direction (a new monomer arrives to the right end of the elongating polymer, and elongation is done from left to right).
 
 #include "a3a1_figure_peptide_bond.typ"
+
+#block-note[
+Now we should point at a protein chemistry-specific terminology issue: we
+      have seen that a protein is a polymer made of a number of monomers, called
+      #emph[amino acids]. In protein chemistry, there is a
+      subtlety: once an amino acid has been polymerized into a protein, it is no
+      more called an amino acid, but is called a #emph[residue]
+      instead.  We may say that a residue is an amino acid less a water
+      molecule. ]