1. Now, we need to attach the other AA (aminoadipic acid) –First we need to selectively deprotect (at cys) to give the free amine

2. Deprotection: Note: You will not be required to know mechanism for removal of BOC with acid. You are req’d to know that H + removes BOC to give amine

4. Solution-phase synthesis is very long –Okay for small peptides (~2-4) For longer peptides, we use solid-phase supported synthesis –Similar to oligonucleotide solid-phase synthesis (CPG) Uses protection/activation strategy Molecule is attached to solid support The first peptide synthesis on a solid support was performed by Merrifield (first reported in 1963; Nobel Prize in 1984) –Polystyrene resin beads (support) –Support is functionalized for attachment –There have since been several modifications to the resin –Can make ~ 30 – long peptides with high efficiency ~99% / step (0.99) 30 = 75% yield

5. Overall synthesis Standard for proteingenic AA’s, but technique can be used for the non-proteingenic AA’s