Bibliographic Information Self-gelatinizable copolymer immobilized glucose biosensor based on prussian blue modified graphite electrode

Sizin üçün oyun:

Google Play'də əldə edin


Yüklə 234.69 Kb.
səhifə1/5
tarix26.08.2018
ölçüsü234.69 Kb.
  1   2   3   4   5

Bibliographic Information
Self-gelatinizable copolymer immobilized glucose biosensor based on prussian blue modified graphite electrode. Deng Q; Li B; Dong S Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, China ANALYST (1998 Oct), 123(10), 1995-9. Journal code: 4OS. ISSN:0003-2654. Journal; Article; (JOURNAL ARTICLE) written in English. AN 1999226373 MEDLINE (Copyright 2001 U.S. National Library of Medicine)
Abstract
A novel poly(vinyl alcohol) grafting 4-vinylpyridine self-gelatinizable copolymer was adapted to immobilize glucose oxidase. The reduction of hydrogen peroxide (H2O2) was detected at a Prussian Blue (PB) modified graphite electrode. A stable and sensitive glucose amperometric biosensor is described. The copolymer is a good biocompatible polymer in which the glucose oxidase retains high activity. Moreover, the copolymer can adhere firmly to the inorganic PB membrane. The sensor showed an apparent Michaelis-Menten constant of 18 +/- 0.2 mM and a maximum current density of 1.14 microA cm-2 mM-1. The linear range is from 5 microM to 4.5 mM glucose and the detection limit is 0.5 microM glucose. The catalytic efficiency of PB for the reduction of H2O2 is higher than that for the oxidation of H2O2. Glucose concentrations in serum samples from healthy persons and diabetic patients were determined using the sensor. The results compared well with those provided by the hospital using a spectroscopy method.
Bibliographic Information
Characterization of the structural and functional changes of hemoglobin in dimethyl sulfoxide by spectroscopic techniques. Liu C; Bo A; Cheng G; Lin X; Dong S Laboratory of Electroanalytical Chemistry and National Analysis and Research Center of Electrochemistry and Spectroscopy, Changchun, Jilin 130022, China BIOCHIMICA ET BIOPHYSICA ACTA (1998 Jun 11), 1385(1), 53-60. Journal code: A0W. ISSN:0006-3002. Journal; Article; (JOURNAL ARTICLE) written in English. AN 1998296076 MEDLINE (Copyright 2001 U.S. National Library of Medicine)
Abstract
Circular dichroism (CD), fourier transform infrared (FTIR), and fluorescence spectroscopy were used to explore the effect of dimethyl sulfoxide (DMSO) on the structure and function of hemoglobin (Hb). The native tertiary structure was disrupted completely when the concentration of DMSO reached 50% (v/v), which was determined by loss of the characteristic Soret CD spectrum. Loss of the native tertiary structure could be mainly caused by breaking the hydrogen bonds, between the heme propionate groups and nearby surface amino acid residues, and by disorganizing the hydrophobic interior of this protein. Upon exposure of Hb to 52% DMSO for ca. 12 h in a D2O medium no significant change in 1652 cm-1 band of the FTIR spectrum was produced, which demonstrated that alpha-helical structure predominated. When the concentration of DMSO increased to 57%: (1) the band at 1652 cm-1 disappeared with the appearance of two new bands located at 1661 and 1648 cm-1; (2) another new band at 1623 cm-1 was attributed to the formation of intermolecular beta-sheet or aggregation, which was the direct consequence of breaking of the polypeptide chain by the competition of S&z.dbnd6;O groups in DMSO with C&z.dbnd6;O groups in amide bonds. Further increasing the DMSO concentration to 80%, the intensity at 1623 cm-1 increased, and the bands at 1684, 1661 and 1648 cm-1 shifted to 1688, 1664 and 1644 cm-1, respectively. These changes showed that the native secondary structure of Hb was lost and led to further aggregation and increase of the content of 'free' amide C&z.dbnd6;O groups. In pure DMSO solvent, the major band at 1664 cm-1 indicated that almost all of both the intermolecular beta-sheet and any residual secondary structure were completely disrupted. The red shift of the fluorescence emission maxima showed that the tryptophan residues were exposed to a greater hydrophilic environment as the DMSO content increased. CO-binding experiment suggested that the biological function of Hb was disrupted seriously even if the content of DMSO was 20%. Copyright 1998 Elsevier Science B.V. All rights reserved.
Bibliographic Information
Synthesis of a self-gelatinizable grafting copolymer of poly(vinyl alcohol) for construction of an amperometric peroxidase electrode. Li B; Niu L; Kou W; Deng Q; Cheng G; Dong S Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, China ANALYTICAL BIOCHEMISTRY (1998 Feb 1), 256(1), 130-2. Journal code: 4NK. ISSN:0003-2697. Journal; Article; (JOURNAL ARTICLE) written in English. AN 1998131757 MEDLINE (Copyright 2001 U.S. National Library of Medicine)
Bibliographic Information
Scanning tunnelling microscopy observation of cytochrome-c denaturation induced by bromopyrogal red on highly oriented pyrolytic graphite. Zhang B; Zhu Y; Dong S; Wang E Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, People's Republic of China INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES (1997 Oct), 21(3), 251-61. Journal code: AY6. ISSN:0141-8130. Journal; Article; (JOURNAL ARTICLE) written in English. AN 1998013648 MEDLINE (Copyright 2001 U.S. National Library of Medicine)
Abstract
The denaturation of cytochrome-c (cyt-c) induced by bromopyrogal red (BPR) was studied by scanning tunnelling microscopy (STM) on the electrochemically pretreated highly oriented pyrolytic graphite (HOPG) surface. STM images reveal that denatured cyt-c molecules exist in variable states including aggregates, globular compact, partially unfolded and combined with BPR molecule. The apparently low image contrast of denatured cyt-c observed in this experiment comparing to that of native cyt-c molecules, and the relative low image contrast of the unfolded part comparing with the compact globular part, are ascribed to the unfavourable tunnelling paths for the conformational variations of denatured cyt-c molecules.
Bibliographic Information
Preparation of metal ion sensor. Li, Jinghong; Dong, Shaojun. (Changchun Applied Chemistry Institute, Chinese Academy of Sciences, Peop. Rep. China). Faming Zhuanli Shenqing Gongkai Shuomingshu (1998), 5 pp. CODEN: CNXXEV CN 1186237 A 19980701 Patent written in Chinese. Application: CN 96-11479 19961226. CAN 132:205100 AN 2000:151809 CAPLUS (Copyright 2001 ACS)
Patent Family Information
Patent No. Kind Date Application No. Date

CN 1186237 A 19980701 CN 1996-114793 19961226




Abstract
The sensor is prepd. by pre-treating Au electrode by chem. and electrochem. cleaning and drying, impregnating the electrode in ethanol or acetone soln. contg. alkyl thiol for 1 min-2 d, washing with ethanol and water, drying under N2, spreading a mixed soln. of trichloromethane and methanol contg. 0.1-1.0 mg ml-1 phospholipid onto water surface, holding for 10-40 min to volatilize org. solvent, forming a monomol. layer of phospholipid, dipping the Au electrode through the monomol. layer into water, incubating the electrode with phospholipid film in a soln. contg. valinomycin or monensin for 5-20 h, and washing. The phospholipid may be phosphatidylcholine, dilauroylcholine, dipalmitoylcholine, phosphatidylethanolamine, phosphatidylserine, or phosphatidylinositol.
Bibliographic Information
Preparation of biological sensor by coating-freezing method. Dong, Shaojun; Li, Jinghong; Ding, Lin; Wang, Erkang. (Changchun Applied Chemistry Inst., Chinese Academy of Sciences, Peop. Rep. China). Faming Zhuanli Shenqing Gongkai Shuomingshu (1998), 5 pp. CODEN: CNXXEV CN 1186225 A 19980701 Patent written in Chinese. Application: CN 96-11479 19961226. CAN 132:163118 AN 2000:151808 CAPLUS (Copyright 2001 ACS)
Patent Family Information
Patent No. Kind Date Application No. Date

CN 1186225 A 19980701 CN 1996-114794 19961226




Abstract
The process comprises treating Au electrode by oxidizing with concd. H2SO4-30% H2O2 (7:3), drying under N2, modifying with 1-10 mM C10-20 alkylthiol/ethanol or hexane soln. to obtain thiol membrane on the surface of Au electrode, coating with 10-30 mg/mL phosphatidylinositol-choline/decane soln., incubating in valinomycin-monensin soln. for 6-24 h, freezing at (-5)-(-20°), and washing.
Bibliographic Information
Preparation of poly(vinyl alcohol) graft copolymer with 4-vinyl pyridine. Li, Bin; Kou, Wenpeng; Dong, Shaojun. (Changchun Applied Chemistry Inst., Chinese Academy of Sciences, Peop. Rep. China). Faming Zhuanli Shenqing Gongkai Shuomingshu (1998), 5 pp. CODEN: CNXXEV CN 1186082 A 19980701 Patent written in Chinese. Application: CN 96-12352 19961225. CAN 132:152370 AN 2000:140808 CAPLUS (Copyright 2001 ACS)
Patent Family Information
Patent No. Kind Date Application No. Date

CN 1186082 A 19980701 CN 1996-123527 19961225




Abstract
Title graft polymer is prepd. by graft polymn. of 2-10% poly(vinyl alc.) (mol. wt. 30,000-115,000) with 0.2-1.5% 4-vinylpyridine in the presence of ammonium cerium nitrate initiator at 20°-40° for 2.5-3.5 h, then pptg. the product with 3-6 fold of methanol, washing with methanol, and drying in vacuum, wherein O2 is removed by vacuumizing for 50-80 min before reaction.
Bibliographic Information
Preparation of biological sensor by latex embedded enzyme. Dong, Shaojun; Cheng, Guangjin; Li, Bin; Kou, Wenming; Zhang, Jinzhong. (Changchun Applied Chemistry Inst., Chinese Academy of Sciences, Peop. Rep. China). Faming Zhuanli Shenqing Gongkai Shuomingshu (1998), 5 pp. CODEN: CNXXEV CN 1186115 A 19980701 Patent written in Chinese. Application: CN 96-12352 19961225. CAN 132:75677 AN 2000:59530 CAPLUS (Copyright 2001 ACS)
Patent Family Information
Patent No. Kind Date Application No. Date

CN 1186115 A 19980701 CN 1996-123528 19961225

CN 1046549 B 19991117


Abstract
The raw material is composed of 2-5% poly(vinyl alc.)-4-vinylpyridine graft copolymer 0.15-0.30 mL, enzyme 0.5-3.0 mg, and/or 0.01M K ferricyanide. The process comprises mixing the raw material, coating on the surface of electrode, and standing at (-20)-4°C for 16-24 h. The enzyme is selected from glucose oxidase, horseradish peroxidase, and polyphenol oxidase.
Bibliographic Information
Preparation of hydrogels for enzyme immobilization to be used in biosensors. Dong, Shaojun; Guo, Yizhu. (Changchun Applied Chemistry Institute, Chinese Academy of Sciences, Peop. Rep. China). Faming Zhuanli Shenqing Gongkai Shuomingshu (1996), 5 pp. CODEN: CNXXEV CN 1118376 A 19960313 Patent written in Chinese. Application: CN 94-10866 19940906. CAN 130:248765 AN 1999:245147 CAPLUS (Copyright 2001 ACS)
Patent Family Information
Patent No. Kind Date Application No. Date

CN 1118376 A 19960313 CN 1994-108666 19940906

CN 1049009 B 20000202


Abstract
Described is method for the prepn. of hydrogels with improved strength by freezing at -4°.apprx.-10° for 10.apprx.20 h an aq. soln. contg. cellulose 0.1.apprx.10% and poly(vinyl alc.) 5.apprx.25%. The method can be used for immobilizing enzymes by dissolving an enzyme (e.g. peroxidase, cholesterol oxidase, tyrosine oxidase, alc. oxidase, alc. dehydrogenase, lactase, lactate dehydrogenase, glycerin dehydrogenase, choline esterase, lipase, or phosphoesterase) along with a medium (e.g. potassium ferricyanide, ferrocene and its deriv., quinones, and org. dyes) into the above soln. and freezing the soln. to form a gelled membrane contg. an immobilized enzyme. The membrane can then be placed on an electrode for the prepn. of biosensors. Alternatively, the enzyme-contg. hydrogel soln. can be used for direct coating of the electrode. The sensor showed biocatalytic action in org. solvents such as chloroform, dichloroethane, chlorobenzene, dioxane, acetonitrile, acetone, methanol, ethanol, cyclohexanone, UHF, N,N- DMA, etc.
Bibliographic Information
Manufacture of heat treated stable catalytic oxygen reducing electrodes. Dong, Shaojun; Jiang, Rongzhong. (Changchun Applied Chemistry Institute, Chinese Academy of Sciences, Peop. Rep. China). Faming Zhuanli Shenqing Gongkai Shuomingshu (1996), 5 pp. CODEN: CNXXEV CN 1135664 A 19961113 Patent written in Chinese. Application: CN 95-10491 19950510. CAN 130:215074 AN 1999:202143 CAPLUS (Copyright 2001 ACS)
Patent Family Information
Patent No. Kind Date Application No. Date

CN 1135664 A 19961113 CN 1995-104915 19950510



CN 1052117 B 20000503


Abstract
Heat treated Fe (or Co) tetra-Ph porphyrin modified O reducing electrodes are prepd. by: dipping a glassy C electrode in a concd. H2SO4-K2Cr2O7 soln. overnight, cleaning the electrode, polishing the electrode surface with 300-mesh MgO or 1-mm a-Al2O3, adding 0.2-0.5 g powd. Fe tetra-Ph porphyrin on the polished surface, covering the powder layer with a polished surface of another glassy C electrode, rubbing the electrodes against each other to evenly distribute and tightly attach the powder on electrode surface, laying the electrodes horizontally in a quartz tube, sealing the tube in N, heating the sealed tube in a N atm. in a quartz tube furnace at 500-800° for 0.5-2 h, cooling to .apprx.20°, washing the heat treated electrode, and drying.
Bibliographic Information
Dimerization of hydroxylated species of m-aminophenol by cytochrome c with hydrogen peroxide. Zhu, Yimin; Li, Jinghong; Dong, Shaojun. Laboratory of Electroanalytical Chemistry, Chinese Academy of Sciences, Jilin, Peop. Rep. China. J. Mol. Catal. B: Enzym. (1998), 5(5-6), 475-482. CODEN: JMCEF8 ISSN: 1381-1177. Journal written in English. CAN 130:135781 AN 1998:804964 CAPLUS (Copyright 2001 ACS)
Abstract
The cytochrome c and hydrogen peroxide-dependent oxidn. of m-aminophenol was investigated by electrochem. and spectrophotometry. The results indicated that the hydroxylated species of m-aminophenol have at least two conjugated substituted groups on the ring system (most possibly, its oxidized form 2-hydroxy-4-iminoquinone), and that the degrdn. of cytochrome c by hydrogen peroxide can also be prevented in the presence of m-aminophenol. The hydroxyl radical scavengers, mannitol and sodium benzoate, almost completely eliminate the hydroxylation of m-aminophenol. But oxo-heme species scavenger, uric acid, does not inhibit the hydroxylation. Combining the results of mass spectrum, NMR and element anal. with that of spectrophotometry, electrochem. and chem. scavengers, it is suggested that cytochrome c may act as a peroxidase, which facilitates the hydroxylation and subsequent dimerization of m-aminophenol.
Bibliographic Information
Molecular design based on hydrogen bond. Zhao, Jianwci; Niu, Li; Dong, Shaojun. Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Peop. Rep. China. Fenxi Huaxue (1998), 26(11), 1362-1364. CODEN: FHHHDT ISSN: 0253-3820. Journal written in Chinese. CAN 130:133644 AN 1998:777656 CAPLUS (Copyright 2001 ACS)
Abstract
Mol. recognition based upon the hydrogen bond has important bearing on related processes occurring in biol. body. In this work, a series of mol. which can form double hydrogen bond with dopamine quinone (DQ) have been designed, and the final heat of formation of recognition mol. (HA), DQ(HB) and their complex (HAB) have also been calcd. resp. by Austin Model 1 (AM1) method. The decrease of DH(DH = HAB - (HA + HB)) with the increasing of the distance between double amino groups is found in our calcn. results. Thus, the matching of microdomain environment is an important factor that should be considered in mol. designs.
Bibliographic Information
Electrochemistry of heteropolyanions in coulombically linked self-assembled monolayers. Liu, Shaoqin; Tang, Zhiyong; Bo, Aili; Wang, Erkang; Dong, Shaojun. Changchun Institute of Applied Chemistry, and National Analysis and Research Center of Electrochemistry and Spectroscopy, Laboratory of Electroanalytical Chemistry, Academic Sinica, Changchun, Peop. Rep. China. J. Electroanal. Chem. (1998), 458(1-2), 87-97. CODEN: JECHES ISSN: 0368-1874. Journal written in English. CAN 130:130946 AN 1998:721054 CAPLUS (Copyright 2001 ACS)
Abstract
A composite film contg. heteropolyanion was fabricated on gold by attaching the Keggin-type heteropolyanion, PMo12O403-, on a 4-aminothiophenol SAM via Au-S bonding. Reflection FTIR, cyclic voltammogram and XPS were used for the characterization of the composite film. Reflection FTIR studies indicate that there is some Coulombic interaction between PMo12O403- and the surface amino group in the composite film, which greatly improves the film stability and prevents effectively the destructive intermol. aggregation. The composite film shows three reversible redox couples within the pH range pH£7.0, attributed to three two-electron and two-proton electrochem. redn.-oxidn. processes of PMo12O403-. Compared with PMo12O403- in the soln., the PMo12O403- of the composite film electrode can exist in a larger pH range, and shows smaller peak-to-peak sepn., and more reversible reaction kinetics. Also, the composite film obtained shows a good catalytic activity for the redn. of BrO3-.
Bibliographic Information
Self-gelatinizable copolymer immobilized glucose biosensor based on Prussian Blue modified graphite electrode. Deng, Qing; Li, Bin; Dong, Shaojun. Changchun Institute of Applied Chemistry, Laboratory of Electroanalytical Chemistry, Chinese Academy of Sciences, Changchun, Peop. Rep. China. Analyst (Cambridge, U. K.) (1998), 123(10), 1995-1999. CODEN: ANALAO ISSN: 0003-2654. Journal written in English. CAN 130:49315 AN 1998:644121 CAPLUS (Copyright 2001 ACS)
Abstract
A novel poly(vinyl alc.) grafting 4-vinylpyridine self-gelatinizable copolymer was adapted to immobilize glucose oxidase. The redn. of hydrogen peroxide (H2O2) was detected at a Prussian Blue (PB) modified graphite electrode. A stable and sensitive glucose amperometric biosensor is described. The copolymer is a good biocompatible polymer in which the glucose oxidase retains high activity. Moreover, the copolymer can adhere firmly to the inorg. PB membrane. The sensor showed an apparent Michaelis-Menten const. of 18±0.2 mM and a max. c.d. of 1.14 mA cm-2 mM-1. The linear range is from 5 mM to 4.5 mM glucose and the detection limit is 0.5 mM glucose. The catalytic efficiency of PB for the redn. of H2O2 is higher than that for the oxidn. of H2O2. Glucose concns. in serum samples from healthy persons and diabetic patients were detd. using the sensor. The results compared well with those provided by the hospital using a spectroscopy method.
Bibliographic Information
Microelectrode voltammetric measurement of heterogeneous electron transfer rate constants for reduction of 7,7,8',8'-tetracyanoquinodimethane in polymer electrolytes. Zhou, Huafang; Ding, Liming; Gu, Ningyu; Dong, Shaojun. Lab. Electroanalytical Chem., Changchun Inst. Applied Chem., Chinese Acad. Sci., Jilin, Peop. Rep. China. Electrochim. Acta (1998), 43(21-22), 3353-3358. CODEN: ELCAAV ISSN: 0013-4686. Journal written in English. CAN 129:282548 AN 1998:590366 CAPLUS (Copyright 2001 ACS)
Abstract
This paper presents a microelectrode voltammetric detn. of heterogeneous electron transfer rate consts. (ks) and diffusion coeffs. (D) of 7,7,8',8'-tetracyanoquinodimethane (TCNQ) in polyelectrolytes. The diffusion coeffs. are estd. using cyclic voltammetry under linear diffusion conditions, and the heterogeneous electron transfer rate consts. were obtained under mixed linear and radial diffusion in the polyelectrolyte. Ks and D increase with increasing temp., and the activation barriers of the electrode reaction for redn. of TCNQ were obtained. However, the dependencies of D and ks of TCNQ on the size and charge of the counterion are compared in the polyelectrolyte.
Bibliographic Information
Electrocatalytic reduction of nitrite with heteropolyanions deposited on carbon electrodes. Xi, Xiaodan; Liu, Shaoqin; Wang, Enbo; Liu, Baifeng; Dong, Shaojun. Laboratory of Electroanalytic Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Peop. Rep. China. Fenxi Huaxue (1998), 26(6), 719-723. CODEN: FHHHDT ISSN: 0253-3820. Journal written in Chinese. CAN 129:62097 AN 1998:425070 CAPLUS (Copyright 2001 ACS)
Abstract
Electrochem. behavior of Dawson-type P2W18O626- deposited on a glassy carbon electrode, Keggin-type SiMo12O404- and its derivs. Dy(SiMo11O39)213- deposited on a pyrolytic graphite electrode was described. All three modified electrodes displayed catalytic activity for nitrite redn. in acidic solns. and the catalytic current is linear to the square root of nitrite concn.
Bibliographic Information
Amperometric Glucose Biosensor Based on Sol-Gel Organic-Inorganic Hybrid Material. Wang, Bingquan; Li, Bin; Deng, Qing; Dong, Shaojun. Laboratory of Electroanalytical Chemistry and National Analysis and Research Center of Electrochemistry and Spectroscopy, Changchun Institute of Applied Chemistry Chinese Academy of Sciences, Jilin, Peop. Rep. China. Anal. Chem. (1998), 70(15), 3170-3174. CODEN: ANCHAM ISSN: 0003-2700. Journal written in English. CAN 129:186239 AN 1998:424980 CAPLUS (Copyright 2001 ACS)
Abstract
A new type of sol-gel org.-inorg. hybrid material was developed and used for the prodn. of biosensors. This material is composed of silica sol and a grafting copolymer of poly(vinyl alc.) with 4-vinylpyridine. It prevents the cracking of conventional sol-gel-derived glasses and eliminates the swelling of the hydrogel. The optimum compn. of the hybrid material was first examd., and then glucose oxidase was immobilized in this matrix to demonstrate its application. The characteristics of the biosensor were studied by cyclic voltammetry and chronoamperometry. The biosensor exhibited a series of good properties: high sensitivity (600 nA mmol-1L-1), short response time (11 s) and remarkable long-term stability in storage (at least 5 mo). In addn., the characteristics of the second-generation biosensor with the use of tetrathiafulvalene as a mediator were discussed.
Bibliographic Information
Characterization of the structural and functional changes of hemoglobin in dimethyl sulfoxide by spectroscopic techniques. Liu, Changwei; Bo, Aili; Cheng, Guangjin; Lin, Xiangqin; Dong, Shaojun. Changchun Institute of Applied Chemistry, Laboratory of Electroanalytical Chemistry and National Analysis and Research Center of Electrochemistry and Spectroscopy, Chinese Academy of Sciences, Changchun, Peop. Rep. China. Biochim. Biophys. Acta (1998), 1385(1), 53-60. CODEN: BBACAQ ISSN: 0006-3002. Journal written in English. CAN 129:132714 AN 1998:380561 CAPLUS (Copyright 2001 ACS)
Abstract
CD (CD), fourier transform IR (FTIR), and fluorescence spectroscopy were used to explore the effect of DMSO (DMSO) on the structure and function of Hb (Hb). The native tertiary structure was disrupted completely when the concn. of DMSO reached 50% (vol./vol.), which was detd. by loss of the characteristic Soret CD spectrum. Loss of the native tertiary structure could be mainly caused by breaking the hydrogen bonds, between the heme propionate groups and nearby surface amino acid residues, and by disorganizing the hydrophobic interior of this protein. Upon exposure of Hb to 52% DMSO for .apprx.12 h in a D2O medium no significant change in 1652 cm-1 band of the FTIR spectrum was produced, which demonstrated that a-helical structure predominated. When the concn. of DMSO increased to 57%: (1) the band at 1652 cm-1 disappeared with the appearance of two new bands located at 1661 and 1648 cm-1; (2) another new band at 1623 cm-1 was attributed to the formation of intermol. b-sheet or aggregation, which was the direct consequence of breaking of the polypeptide chain by the competition of S:O groups in DMSO with C:O groups in amide bonds. Further increasing the DMSO concn. to 80%, the intensity at 1623 cm-1 increased, and the bands at 1684, 1661 and 1648 cm-1 shifted to 1688, 1664 and 1644 cm-1, resp. These changes showed that the native secondary structure of Hb was lost and led to further aggregation and increase of the content of 'free' amide C:O groups. In pure DMSO solvent, the major band at 1664 cm-1 indicated that almost all of both the intermol. b-sheet and any residual secondary structure were completely disrupted. The red shift of the fluorescence emission maxima showed that the tryptophan residues were exposed to a greater hydrophilic environment as the DMSO content increased. CO-binding expt. suggested that the biol. function of Hb was disrupted seriously even if the content of DMSO was 20%.

Dostları ilə paylaş:
  1   2   3   4   5
Orklarla döyüş:

Google Play'də əldə edin


Verilənlər bazası müəlliflik hüququ ilə müdafiə olunur ©muhaz.org 2017
rəhbərliyinə müraciət

    Ana səhifə