BP04 Threading together amino acids via peptide links

Aim: To show that peptides can be built from amino acid building blocks via the formation of peptide links.

Amino acids can be covalently linked to each other by the formation of an amide bond between the alphaamino group of the first amino acid and the alpha-carboxyl group of the second amino acid.

 

   This bond is called a peptide bond or linkage, and the product is called a dipeptide. This reaction is, in fact, a condensation reaction between the carboxyl group of one amino acid and the amino group of the other. We can see that the dipeptide formed still has an amino group (called the Nterminus) at one end and a carboxyl group (C-terminus) at the other end. The reaction can therefore in principle be repeated, with the formation firstly of an oligopeptide (containing only a few amino acids) and secondly a polypeptide as the chain becomes much longer.

When noting down the primary structure that is formed by the peptide bond we use the three letter codes of the amino acids involved.
The oligopeptide

N      Gly-Leu-Ser-Asp      C

indicates the combination of glycine, leucine, serine, and aspartic acid. By convention, the N-terminus is on the left and the C-terminus on the right.