Aldehyde, chemical ligation

Key Words Acidolytic cleavage backbone amide linkage bioconjugate chemical ligation combinatorial chemistry handle linker peptide alcohol peptide aldehyde peptide ester peptide thioester protecting group solid support. 

Figure 1.7 Chemical ligation of aldehyde or ketones with aminoojy or hydrazide peptide derivatives to form oximes or hydrazones, respectively. ...

If ligation through a chosen side chain is desired, it can be introduced in the form of Ne-seryl-Lys, particularly if the fragment in question is to be made by total chemical synthesis. The periodate oxidation of a Ser that has a free N-terminus is so simple and satisfactory that we regard such a residue simply as a protected aldehyde. 

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