Totally Protective Peptides
All reactive protective groups, except those requiring chemical reactions, should be protected to prevent side reactions in subsequent chemical reactions, reduce yield or lead to synthesis failure.Common protective groups are summarized as follows:
Fully Protected Peptide Synthesis Display
For example, Asp-Lys-Gly-Tyr-Linker-Functional Molecules are synthesized here with ethylenediamine as the linker.
Step 1: Synthesis of C-terminal carboxyl-bare fully protective peptide Boc-Asp(OtBu)-Lys(Boc)-Gly-Tyr(tBu)-OH, which can be easily obtained by Fmoc solid-phase synthesis method, only the final structure is shown here.
Step 2: Ethylenediamine is attached to the bare C-terminal carboxyl group (red structure in the figure above), and the structure of Ethylenediamine is as follows
The ratio of raw materials, reaction concentration and reaction time should be controlled or one of the amino groups should be temporarily protected.
The final product Boc-Asp(OtBu)-Lys(Boc)-Gly-Tyr(tBu)-ethylenediamine was obtained with the following structure
Step 3: Combine the other end of the linker arm with a functional small molecule, for example, a functional small molecule contains a carboxyl group, and other groups are not involved in the reaction or are protected.
Step 4: Remove all the protective groups, and choose which kind of protective groups in the early stage depends on the needs of the experiment. Generally, according to the experimental route, after removing the protective groups, we get the desired polypeptide derivatives.The example structure is as follows:
Local protective peptide
Compared with fully protected peptides, local protective peptides do not need full protection of their side chain protective groups, but only protect individual side chain active groups. Their advantages are improved solubility of polypeptides and reduced steric hindrance.In the process of synthesizing polypeptide derivatives, the local protective peptides and the total protective peptides are very similar, so the edition will not further introduce them.