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chemical modification of Silk Proteins: Current Status and Future Prospects

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Advanced Fiber Materials 2022年第4期4卷 705-719页

作者： Haoran Liu Ziyang Sun Chengchen Guo School of Engineering Westlake UniversityHangzhou 310023ZhejiangChina

Silk extracted from the cocoon of silkworm has been used as textile materials for thousands of years.Recently,silk has been redefined as a protein-based biomaterial with great potential in biomedical applications owing to its excellent mechanical properties,biocompatibility,and biodegradability.With the advances in silk processing technologies,a broad range of intriguing silk-based functional biomaterials have been made and applied for various biomedical uses.However,most of these materials are based on natural silk proteins without chemical modification,leading to limited control of properties and functions(e.g.,biodegradability and bioactivity).A chemical toolbox for modifying the silk proteins is required to achieve versatile silk-based materials with precisely designed properties or functions for different applications.Furthermore,inspired by the traditional fine chemical industry based on synthetic chemistry,developing silk-based fine chemicals with special functions can significantly extend the applications of silk materials,particularly in biomedical fields.This review summarizes the recent progress on chemical modification of silk proteins,focusing on the methodologies and applications.We also discuss the challenges and opportunities of these chemically modified silk proteins.

关键词： Silk proteins chemical modification Biomaterials Fine chemicals Biomedical applications

Synthesis of multifunctional additives for solid propellants:Structure,properties and mechanism

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Defence Technology（防务技术） 2024年第3期33卷 308-316页

作者： Pingan Zhang Lina Sun Jianmin Yuan Jianru Deng College of Chemistry and chemical Engineering Hunan UniversityChangsha 410082PR China College of Material Science and Engineering Hunan UniversityChangsha 410082PR China Hu Bei Sanjiang Aerospace Jianghe chemical Technology Co. LtdYichang 444200PR China

To simplify the composite propellant formulation and address the current issue of the single-functionality present in existing additives,the multi-cyano,amine-based polybutadiene(AEHTPB-CN)was prepared based on AEHTPB by adopting appropriate synthesis strategies.By replacing 10% of HTPB binder in the propellant formulation,it can effectively enhance the interfacial bond strength between the propellant binder matrix and solid fillers(AP(ammonium perchlorate)and RDX(cyclotrimethylene-trinitramine)),the mechanical properties of the HTPB/AP/RDX/Al propellant were superior to blank control propellant with an improvement of 35.4% in tensile strength,62.0% enhancement in elongation at break,and reduce the propellant burn rate by 10.7% with any energy loss.The function mechanism of AEHTPB-CN was systematically elucidated through experiments and computer simulation techniques.The results show that the tertiary amine group in AEHTPB-CN can react with AP to form ammonium ionic bonds,and the hydroxyl and cyano groups can form hydrogen bonding interactions with AP,which enables AEHTPB-CN to be firmly adsorbed on the AP surface through chemical and physical interactions.For RDX,the interfacial bonding effect of AEHTPB-CN is attributed to their ability to form C-H···N≡C weak hydrogen bonding interaction between the cyano group and RDX methylene group.

关键词： Hydroxyl-terminated polybutadiene(HTPB) HTPB propellant chemical modification Bonding agent Mechanism

chemical modification and Fluorescence Spectrum of Tryptophan Residues in Pullulanase

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chemical Research in Chinese Universities 2006年第1期22卷 61-64页

作者： TENG Li-rong FAN Hao ZHANG Yuan-yuan YU Qi HUANG Yue-feng LIU Lan-ying College of Life Science Jilin University Changchun 130023 P. R. China

Tryptophan（Trp） residues in a pullulanase were modified by N-bromosuccinimide（NBS）. The results of the Spande method indicate that there are 18 Trp residues in the pullulanase and nine of them are located on the surface af the enzyme. Three of these Trp residues are nonessential residues which show the fastest reaction rate according to the Zou＇s plot. Two of the seven relative faster reacting residues are essential for the activity of the enzyme. The other eight are the slowest in the reaction rate or non-reactive residues for the reaction. The fluorescence and circular dichroism（CD） spectra of the pullulanase have been changed after the reaction with NBS. Potassium iodide（KI） and acrylamide also have remarkable influences on the fluorescence spectra of the pullulanase.

关键词： Pullulanase Tryptophan （Trp） chemical modification Fluorescence spectrum

chemical modification OF THE SURFACE OF CALCIUM ALGINATE GEL BEADS

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Chinese Journal of Polymer Science 2004年第2期22卷 183-186页

作者：萧聪明 College of Materials Science and Engineering Huaqiao University Quanzhou 362011 China

The chemical modification of the surface of calcium alginate gel beads (CAGB) via grafting copolymerization with vinyl acetate (VAc) was studied. The optimum reaction conditions with activation and graft copolymerization two steps were explored. First, 5 grams CAGB with 2.5 mm initial diameter was initiated with 0.0493 mol/L K2S2O8 at 51 °C for 30 min in 15 mL 1 % PVA/H2O. Then 4.34 moi/L VAc was added dropwise and the reaction was allowed to proce at 48 °C for 3 h. The grafting efficiency could come up to 30%. It was found the stability of modified CAGB in the air and in electrolyte solutions was greatly improved.

关键词： Calcium alginate gel bead Vinyl acetate Graft copolymerization chemical modification

chemical modification of Tryptophan Residues in Superoxide Dismutase from Camellia Pollen and Its Fluorescence Spectrum

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chemical Research in Chinese Universities 2005年第5期21卷 562-565页

作者： HE Xiao-hong WU Min LI Shan-yu CHU Yu-zhuo CHEN Jia LIU Lan-ying College of Life Science Jilin University Changchun 130023 P. R. China

The amino acid composition of the superoxide dismutase（SOD） from camellia pollen was measured and the tryptophan（Trp） residues were modified by using N-bromosuccinimide（NBS）. The results show that there are 21 Trp residues in an SOD molecule and seven of which are located on the surface of the enzyme. By researching the fluorescence spectra of the native SOD and the modified SOD, we have found that the emission wavelength of Trp is at 335 nm and the fluorescence intensity will decrease when the enzyme is modified. The results also show that potassium iodide（KI） can significantly quench the fluorescence of the native SOD, but it has a less pronounced effect on the modified enzyme. Glycerin as a surface activation reagent can stabilize the fluorescence of the modified enzyme.

关键词： Superoxide dismutase Tryptophan residue chemical modification Fluorescence spectrum

chemical modification of Amino Acid Residues in Human Plasminogen

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chemical Research in Chinese Universities 2003年第3期19卷 317-319页

作者： LIANGFang SUNHong ZHAOCheng-guang CUITing HONGShui-sheng CHENJia LIULan-ying CollegeofLifeScience JilinUniversityChangchun130023P.R.China ChangchunInstituteofBiologicalProducts Changchun130062P.R.China

The chemical modification of human plasminogen(HPg) was studied with 1-ethyl-3-(3- dimethyl aminopropyl) carbodiimide(EDC), N -acetylimidazole(NAI), 1,2-cyclohexanedione(CHD), chloramine T(Ch-T) and N -bromosuccinimide(NBS) as modifying reagents at its carboxyl group, tyrosine, arginine, methionine and tryptophan residues, respectively. The results indicate that tyrosine and arginine residues are not essential for HPg activity, while carboxyl groups, methionine and tryptophan residues are important for the activity of HPg. The Keech and Farrant′s kinetic analysis reveals that one tryptophan residue, one methionine residue and two carboxyl groups are essential for HPg activity.

关键词： Human plasminogen(HPg) chemical modification Carboxyl group Methionine Tryptophan

Effects of chemical modification on physicochemical properties and adsorption behavior of sludge-based activated carbon

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Journal of Environmental Sciences 2021年第2期33卷 340-352页

作者： Chunxu Wu Lanfeng Li Hao Zhou Jing Ai Hongtao Zhang Jialin Tao Dongsheng Wang Weijun Zhang School of Environment Tsinghua UniversityBeijing 100084China School of Environment Studies China University of GeosciencesWuhan 430074China State Key Laboratory of Enuironmental Aquatic Chemistry Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China

This study aimed to explore the adsorption performance of sludge-based activated carbon(SBC)towards dissolved organic matters(DOMs)removal from sewage,and investigated the modification effect of different types of chemicals on the structure of synthesized SBC.Waste activated sludge(WAS)was used as a carbon source,and HCl,HNO 3,and Na OH were used as different types of chemicals to modify the SBC.With the aid of chemical activation,the modified SBC showed higher adsorption performances on DOMs removal with maximum adsorption of 29.05 mg/g and second-order constant(k)of 0.1367(L/mol/sec)due to the surface elution of ash and minerals by chemicals.The surface elemental composition of MSBC suggested that the content of C-C and C-O functional groups on the surface of modified sludge-based activated carbon(MSBC)played an important role on the adsorption capacities of MSBC towards DOMs removal in sewage.Additionally,the residual molecular weight of DOMs in sewage was investigated using a 3-dimension fluorescence excitationemission matrix(3 D-EEM)and high-performance size exclusion chromatography(HP-SEC).Results showed that the chemical modification significantly improved the adsorption capacity of MSBC on humic acids(HA)and aromatic proteins(APN),and both of Na OH-MSBC and HCl-MSBC were effective for a wide range of different AMW DOMs removal from sewage,while the HNO 3-MSBC exhibited poorly on AMW organics of 2,617 Da and 409 Da due to the reducing content of macropore.In brief,this study provides reference values for the impact of the chemicals of the activation stage before the SBCs application.

关键词： Sludge-based activated carbon chemical modification Adsorption Dissolved organic matter

Dyeing of Polyester and Nylon with Semi-synthetic Azo Dye by chemical modification of Natural Source Areca Nut

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Natural Products and Bioprospecting 2018年第1期8卷 23-29页

作者： Ashitosh B.Pawar Sandeep P.More R.V.Adivarekar Department of Fibers and Textile Processing Technology Institute of Chemical TechnologyMumbaiIndia

Various azo compounds(Modified dyes)have been synthesised by chemical modification of areca nut extract(epicate-chin),a plant-based Polyphenolic compound to get semi-synthetic dyes.Three different primary amines namely p-nitro aniline,p-anisidine and aniline,were diazotized to form their corresponding diazonium salts which were further coupled with an areca nut extract.Preliminary characterization of the areca nut extract and the resultant azo compounds(Modified dyes)was carried out in terms of melting point,solubility tests,thin layer chromatography,UV-Visible and FTIR spectroscopy.These modified dyes were further applied on polyester and nylon fabrics and%dye exhaustion was evaluated.Dyed fabrics were further tested for their fastness properties such as wash fastness,rubbing fastness,light fastness and sublimation fastness.The results of the fastness tests indicate that,all the three modified dyes have good dyeability for polyester and nylon fabrics.The dyed fabrics were also tested for ultraviolet protection factor which showed very good ultraviolet protection.

关键词： Semi-synthetic azo dye chemical modification Modified dyes Areca nut Ultraviolet protection factor

Rapid Selection of Phage Se-scFv with GPX Activity via Combination of Phage Display Antibody Library with chemical modification

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chemical Research in Chinese Universities 2007年第1期23卷 58-63页

作者： LIN Feng LI Ying YANG Wen-kui LIANG Bing MU Ying SUN Ye LI Wei LUO Gui-min Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education College of Life Science Jilin University Changchun 130021 P. R. China

Glutathione peroxidase（GPX） plays an important role in scavenging reactive oxygen species. A series of catalytic antibodies with GPX activity have been generated by the authors of＇ this study. To obtain humanized catalytic antibodies, the phage-displayed human antibody library was used to select novel antibodies by repetitive screening, Phage antibodies, scFv-B8 and scFv-H6 with the GSH-binding site, were obtained from the library by enzyme-linked immu- nosorbent assay（ELISA） analysis with 4 rounds of scelection against their respective haptens, S-2,4-dinitriphenyl t-butyl ester（GStI-s-DNP-Bu） and S-2,4-dinit,-iphenyl t-hexyl ester（GSH-s-I）NP-He）. Nevertheless, several studies need to be condueted to determine whether scFv-B8 and seFv-tI6 possess GPX activity. 1＇o enhance the speed of the selection, selenocysteine（Sec, the catalytic group of GPX） was incorporated directly into the phages, scFv-B8 and seFv-H6, by chemical mutation to form the phages Se-scFv-B8 and Se-scFv-H6. The GPX activities were found to be 3012 units/μmol and 2102 units/μmol, respectively. To improve the GPX activity of the phage Se-scFv-B8, DNA shuffling was used to construct a secondary library and another positive phage antibody scFv-B9 was screened out by another panning against GSH-s-DNP-Bu. When Sec was incorporated via chemical mutation into the phage antibody scFv-B9, its GPX activity reached 3560 units/μmol, which is 1.17-fold higher than the phage antibody Se-scFv-B8 and almost approached the order of magnitude of native GPX. The rapid selection is the prerequisite for generating humanized Se-seFv with GPX activity.

关键词： Single chain Fv chemical modification DNA shuffling Glutathione peroxidase Phage display antibody library Selection Selenium Antibody humanization