Chemistry
The Role of Protective Groups in Solid-Phase Peptide Synthesis
Quick fact
In solid-phase peptide synthesis, the amino acid's N-terminus is protected with a group that can be removed selectively, while side-chain protection prevents unwanted reactions. The development of orthogonal protecting groups enabled automated synthesis of long peptides and was recognized with the 1984 Nobel Prize in Chemistry for Bruce Merrifield.
Why this is interesting
You want to assemble a chain of amino acids in a precise order, but each amino acid has multiple reactive sites. How do chemists avoid the wrong reactions and build the correct peptide?