Peptide Bond
The amide linkage joining the carboxyl group of one amino acid to the amino group of the next.
Formula / equation
–CO–NH–
Unit
Dimensionless
In depth
Delocalisation of the nitrogen lone pair into the carbonyl gives the bond partial double bond character, so the peptide unit is planar and cannot rotate. This rigidity restricts the conformations a protein chain can adopt and makes regular secondary structures possible.
Examples in the real world
Two amino acids condensing to a dipeptide with the loss of water; the backbone of every protein.