Separation And Purification Of Cytochrome C By Using Polyniobates Modified Metal-organic Frameworks

Metal organic frameworks(MOFs)materials have been widely used in separation and purification.However,most of MOFs materials easily decomposed in aqueous solution,which limits the investigations on separation/purification in aqueous environment.In this assay,Lindqvist-type polyniobates(K₇H[Nb₆O₁₉]·13H₂O])is modified on titanium-containing metal-organic framework MIL-125(Ti)via hygrogen bond interaction to improve the stability of MIL-125(Ti)obtain the composite through intermolecular hydrogen bonds,and an aqueous-stable composite Nb₆O₁₉/MIL-125(Ti)is successfully prepared.SEM,TEM,XRD,FT-IR,TG,BET,Zeta potential,EDS and water contract angle,suggest that Nb₆O₁₉/MIL-125(Ti)has good surface interface properties,such as large pore size,strong hydrophobicity and rich negative charge.Cytochrome C(Cyt-C)is selected as the model protein to study the separation/purification property of Nb₆O₁₉/MIL-125(Ti).Under the optimal circumanstance(p H=10.0,C_I=0.04 mol·L^-1),the adsorption efficiency of 300?L 100?g·m L^-1 Cyt-C onto 1.0 mg Nb₆O₁₉/MIL-125(Ti)is 99.5%.The adsorption behavior of Cyt-C fits well with the Langmuir adsorption model,and the maximum theoretical adsorption capacity of is 168.35 mg·g^-1.In addition,the Cyt-C absorpted on Nb₆O₁₉/MIL-125(Ti)can be easily recovered by using 3 mol·L^-1Na Cl as eluent,which gives rise to an elution efficiency of 92.19%.Circular dichroism shows that the?-helical conformation of Cyt-C changes silghtly during the adsorption and desorption processes,demonstrating the favorable biocompatibility of Nb₆O₁₉/MIL-125(Ti)composite.In addition,the results of sodium dodecylsulfonate-polyacrylamide gel electrophoresis(SDS-PAGE)analysis demonstrate the successuful separation/purification of Cyt-C from complex sample,e.g.,scrofa heart.After the purification of Cyt-C,the supernatant of porcine heart sample is analysed via mass spectra.Interstingly,498 protein species are identified,including 42 newly found proteins and low abundant proteins,such as Superoxide dismutase 1,IF rod domain-containing protein and Ubiquitin-60S ribosomal protein L40.In suammry,this study prepared aqueous-satble MOFs composite Nb₆O₁₉/MIL-125(Ti),purified Cyt-C from complex real sample,and provide new approach for identifying new/low-abundant proteins in scrofa heart proteomics.