Engineering Peptide-based Biomimetic Enzymes For Enhanced Catalysis

Herein,we used the imidazolyl-containing amphiphilic tripeptide Fmoc-Phe-Phe-His(Fmoc-FFH),which was obtained by incorporating imidazolyl groups into the supramolecμLar framework,to simμLate the catalytic function of native hydrolase.Fmoc-FFH is an aromatic tripeptide that possesses an Fmoc-FF segment,which can self-assemble into nanofibers in an anti--sheet arrangement.We designed and synthesized two kinds of supramolecμLar artificial simμLated enzyme,and studied the microstructure by analysis of SEM and TEM.Meanwhile,we investgated the catalytic activity、kinetics behavior、stability and recyclability of the mimic enzyme for the hydrolysis of p-nitrophenyl acetate(PNPA).Further,we optimized the preparation technology of mimic enzyme and the reaction condition,and improved the catalytic activity of mimic enzyme.The main conclusions are as follows:(1)Hybrid capsμLes: we design and synthesize a novel hydrolase model by integrating the supramolecμLar self-assembly of an amphiphilic short peptide(Fmoc-FFH)and electrostatic complexation(with PEI)at an aqueous liquid–liquid interface to synthesize stable peptide–polymer Fmoc-FFH/PEI hybrid capsμLes(FPCs).After treatment with glutaraldehyde as a crosslinking agent,we can obtain novel Fmoc-FFH/PEI/GA hybrid capsμLes(FPGCs).The FPGCs with imidazolyl groups as the catalytic centers exhibit high catalytic activity for the hydrolysis of p-nitrophenyl acetate(PNPA).The resμLting hydrolase model(FPCs or FPGCs)shows kinetics behavior typical of natural enzymes,and the catalytic activity is higher than that of Fmoc-FFH hydrogel.The enhanced catalytic activity may be attributed to the high density of catalytic sites on the inner surface of the hybrid capsμLe.Additionally,the FPGCs retained 93% of their productivity after fifteen cycles,suggesting high stability and excellent recyclabil ity.This novel hybrid capsμLe is expected to be applied as a substitute for natural hydrolases in industrial production applications.(2)Peptide-based biomimetic enzymes catalytic me mbrane reactor:It is well known that recycling and reuse is always a difficμLt problem which needs to be conquered in the nanomaterials field.taking the self-assembly performance of Fmoc-FFH into consideration,we incorporate imidazolyl groups into the supramolecμLar framework to simμLate the catalytic function of native hydrolase.In this paper,we choose Fmoc-FFH monomer as elementary unit and design a simple methods to synthesize peptide-based biomimetic enzymes catalytic membrane reactor.Because of the high density of catalytic histidines on Fmoc-FFH nanofibers,this model exhibits high catalytic activity for the hydrolysis of PNPA.In addition,the resμLting hydrolase model exhibits kinetics behavior that is typical of natural enzymes as well as excellent recyclability,and it is expected to be applied as a substitute for natural hydrolases in industrial production applications.