Synthesis And Characterization Of Polypeptides Based On Glutamate Derivatives

Peptide hydrogel has gained a lot of focus due to its excellent biofunctionability biodegradability and biological function.However,the common method to prepare peptide hydrogel is solid-phase peptide synthesizer?SPPS?,which is very expensive,time-consuming and low-yielding.All these shortcomings limit their application in biomedicine.In this paper,the block oligopeptides and PBLG homololymer were synthesized by HMDS?Hexamethyl Disilazane?initiated ring opening polymerization?ROP?of Amino acid-N-carboxyl–cycloanhydride?NCA?,this method is very simple and low-cost.The functionalized polypeptide materials were prepared by benzyl glutamate?BLG?and phenylalanine?Phe?,valine?Val?,tyrosine?Tyr?,and combined with the modification?aminolysis reaction and alcoholysis reaction?in the peptide side chains.The results are as follows:1.The oligopeptide containing Phe or Val as hydrophobic segments:The oligopeptide were extremely hydrophobic or hydrophilic with different degree of polymerization?DP?in water.It is the highest success rate only when using ethanol amine?EA?during the aminolysis reaction.In additions,the Phe has a stronger hydrophobicity than Val because of its strong?-?interaction.In addition,we synthesized the large-molecular-weight poly?benzyl glutamate?homopolymer?PBLG?using diinitiators?HMDS and TBD?,We carried out the aminolysis and alcoholysis experiments of PBLG with ethanolamine and ethylene glycol,respectively.The studies have shown that the aminolysis of PBLG still has a very high efficiency,and the use of TBD as a catalyst for the alcoholysis of PBLG will lead to the degradation of PBLG segments.2.The block oligopeptide prepared by BLG and Tyr:It was found that the nonionic peptide amphiphiles could self-assemble into 1D nano-fibirl structure and the3D network formed by entanglement between the fiber structures to get hydrogel in water.TEM,AFM and SEM characterizations were employed to study the self-assemble behavior.It was found that the effect of peptide chemical parameters include side chain structure,molecular chain length and Phe unit number were important on the hydrogel formation.By adding hydrogen peroxide?H₂O₂?and horseradish peroxidase?HRP?,enzymatic cross-linking of phenol was carried out under the catalysis of enzyme.This greatly affects on the self-assembly behavior,transforming it from the slender nanofibers into the assembled nanogel structures.