phosphorylation modification

Phosphopeptides play an important role in life processes, with phosphorylation occurring at Tyr, Ser, Thr on the peptide,. At present, phosphopeptide synthesis generally uses phosphorylated amino acids, and the ones currently used are monobenzyl phosphorylated amino acids. The connection of phosphorylated amino acids is generally achieved using the HBTU/HOBt/DIEA method. However, there are also drawbacks to using this method to synthesize phosphorylated peptides, especially when synthesizing multi phosphorylated peptides or peptides with longer amino acids. The connection efficiency is low and the final product purity is very low. For this phosphorylated peptide, we consider using the post phosphorylation method, which selectively removes the side chain protecting group of the amino acid to be labeled after the peptide synthesis is completed. For Tyr and Thr, unprotected amino acids on the side chain can be directly used for reaction, while Ser can be quantitatively removed using Fmoc Ser (trt) under 1% TFA/DCM conditions.

After phosphorylation, bisbenzylphosphoramidite and tetrazolium are used to generate the active intermediate of phosphoramidite tetrazolium, which is connected to the hydroxyl group and then oxidized to form phosphoryl groups under peroxy acid to complete the reaction.

At present, there are two main methods for peptide phosphorylation modification:

(1) Introducing appropriately protected phosphorylated amino acids directly into the peptide sequence;

(2) After the peptide sequence is synthesized on resin, the side chain hydroxyl groups of Ser, Tyr, or Thr are phosphorylated.

1) Introducing appropriately protected phosphorylated amino acids directly into the peptide sequence:

First, phosphorylate the amino acids that need to be phosphorylated (Thr, Ser, or Tyr) and protect them appropriately. Then, follow the normal SPPS synthesis process to condense the phosphorylated monomers to the peptide site. This method is easy to operate and has become the main method for peptide unit phosphorylation modification.