Abstract: Methods and protected amino acids useful as building blocks (protected monomers) for the synthesis of peptides and proteins that are selectively modified at one or more side-chain hydroxyl groups. Azide-bearing protecting groups allow the selective deprotection of side-chain hydroxyl groups of amino acids after synthesis of a peptide. Reaction conditions for removal of the azide-bearing protecting group can be selected which are substantially orthogonal to those that will remove ?-amino protecting groups typically employed in peptide synthesis, such that hydroxyl groups protected with the azide-bearing protecting group remain protected during synthesis of the peptide chain. Various protecting groups which are readily available can be used for protecting potentially reactive side chain groups of amino acids in the peptide or protein to be modified.

Abstract: Methods and protected amino acids useful as building blocks (protected monomers) for the synthesis of peptides and proteins that are selectively modified at one or more side-chain hydroxyl groups. Azide-bearing protecting groups allow the selective deprotection of side-chain hydroxyl groups of amino acids after synthesis of a peptide. Reaction conditions for removal of the azide-bearing protecting group can be selected which are substantially orthogonal to those that will remove &agr;-amino protecting groups typically employed in peptide synthesis, such that hydroxyl groups protected with the azide-bearing protecting group remain protected during synthesis of the peptide chain. Various protecting groups which are readily available can be used for protecting potentially reactive side chain groups of amino acids in the peptide or protein to be modified.