An ESR study of spin‐labeled silk fibroin membranes and spin‐labeled glucose oxidase immobilized in silk fibroin membranes

Asakura, Tetsuo; Yoshimizu, Hiroaki; Kakizaki, Mitsuhiro

doi:10.1002/bit.260350509

Cited by 32 publications

(9 citation statements)

References 24 publications

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“…Clark et al (20,21) have successfully applied the spin-labeling EPR technique to enzymes immobilized to polymer beads. More recently, Asakura et al (22) have used EPR methods to study an enzyme entrapped rather than covalently bound in a silk fibroin membrane.…”

Section: Resultsmentioning

confidence: 99%

Spin Labeling and Kinetic Studies of a Membrane‐Immobilized Proteolytic Enzyme

Zhuang

Butterfield

1992

Biotechnology Progress

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Membrane-based bioreactors can greatly influence the rate and extent of chemical reactions and consequently lower the costs associated with the corresponding engineering processes. However, in order to progress in this area, greater understanding of the relationship of the structure and function of bioreactor systems is required. In this study, a proteolytic enzyme, papain (EC 3.4.22.2), was covalently coupled onto the surface of a vinyl alcohol/vinyl butyral copolymer (PVB) membrane employing either glutaraldehyde (GA) or 1,1'-carbonyldiimidazole (CDI). Various kinetic and performance properties of the immobilized papain were studied. It was found that these characteristics of the membrane-bound papain depended on the immobilization method. The CDI-immobilized papain bioreactor was used, although the apparent Michaelis constant, Km, of the CDI-immobilized papain was larger than that of the GA-immobilized enzyme. In separate experiments, a six-carbon spacer was also used between the membrane support and the covalently-linked enzyme. It was found that the insertion of the spacer reduced the disturbance of the enzyme system, resulting in a decreased Km, which was now closer to the value for the free enzyme. Electron paramagnetic resonance (EPR) techniques of spin labeling were used for the first time to examine the conformational change and the active site structure of an enzyme covalently immobilized to a membrane. The structural changes of the active site of papain upon immobilization with and without a spacer were in agreement with the functional properties of the enzyme.

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Section: Resultsmentioning

confidence: 99%

Spin Labeling and Kinetic Studies of a Membrane‐Immobilized Proteolytic Enzyme

Zhuang

Butterfield

1992

Biotechnology Progress

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“…The silk produced by the Bombyx mori silkworm is one of the most valuable starting materials in clothing industry. Besides as a textile fiber, silk is increasingly gaining attention as an attractive material for biotechnological and biomedical applications [1, 2]. This is due to the excellent biocompatibility and biodegradability of silk, in particular its fibrous component, namely silk fibroin.…”

Section: Introductionmentioning

confidence: 99%

Effect of plasma treatment of silk fibroin powder on the properties of silk fibroin powder/polyurethane blend film

Zhu

et al. 2010

Polymer Engineering & Sci

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In this study, silk fibroin powder was treated by dielectric barrier discharge (DBD) plasma. The objective is to improve the performance of the silk fibroin powder/ polyurethane (PU) blend film used in biomechanical field. The scanning electron microscope (SEM) showed that the plasma-treated powder was broken into small particles and the film from the treated powder became homogeneous and dense. Fourier transform infrared spectroscopy (FTIR) revealed that the hydrophobic groups in silk fibroin powder were oxidized during plasma treatment. Little change in chemical composition was found on the surface of the blend film from plasma-treated powder. The fracture strain of the blend film from plasma-treated powder was remarkably raised, whereas its tensile strength was influenced significantly by the plasma treatment conditions. The wetout time of the plasma-treated powder/PU film was shortened considerably. This indicates the improved hydrophilicity of the blend film. In addition, the decreased values of water vapor permeability suggested that the structure of the blend film became dense. This might result from the strong interfacial adhesion between plasma-treated powder and PU. FIG. 11. The effect of power density on the water vapor permeability of blend film from the silk fibroin powder treated for 2 min.

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“…Natural polymers such as cellulose (Kaneko et al, 1980;Kaneko and Yamada, 1981) and cellophane (Milosavljevic and Thomas, 1985) are useful materials as a matrix in which various solid photochemical processes are possible. Silk fibroin forms a transparent membrane when cast from its aqueous solution (Asakura et al, 1990). It is an interesting material to incorporate a luminescent probe for application; the present authors have reported luminescent characteristics of Ru(bpy):' incorporated into a silk fibroin membrane .…”

Section: Introductionmentioning

confidence: 68%

Quenching of Photoexcited 4,4'‐dicarboxy‐2,2'‐bipyridinebis(2,2'‐bipyridine)ruthenium(ii) by Oxygen in Aqueous Solution and in Silk Fibroin Membrane

Kaneko

Iwahata

Asakura

1992

Photochem & Photobiology

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Abstract— Photoluminescence and quenching of 4,4'‐dicarboxy‐2,2'‐bipyridinebis(2,2'‐bipyridine)‐ruthenium(II) complex (Ru(DCbpy)(bpy)22+) in an aqueous solution as well as in a silk fibroin membrane were studied. Emission quenching by oxygen in an aqueous solution showed a linear relationship with respect to oxygen concentration. When the complex was incorporated into a silk fibroin membrane by adsorption from an aqueous solution into a preformed membrane, the photoexcited state of the complex was not quenched by oxygen in an aqueous phase. However, when the complex was incorporated into a silk fibroin membrane by casting a mixture of the complex and silk fibroin, the photoexcited complex was quenched by oxygen in an aqueous phase. In this case the Stern‐Volmer plots showed a downward‐deviating curve indicating heterogeneity of the probe site. Emission intensity decreased with an increase of the water content in the silk fibroin membrane.

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An ESR study of spin‐labeled silk fibroin membranes and spin‐labeled glucose oxidase immobilized in silk fibroin membranes

Cited by 32 publications

References 24 publications

Spin Labeling and Kinetic Studies of a Membrane‐Immobilized Proteolytic Enzyme

Spin Labeling and Kinetic Studies of a Membrane‐Immobilized Proteolytic Enzyme

Effect of plasma treatment of silk fibroin powder on the properties of silk fibroin powder/polyurethane blend film

Quenching of Photoexcited 4,4'‐dicarboxy‐2,2'‐bipyridinebis(2,2'‐bipyridine)ruthenium(ii) by Oxygen in Aqueous Solution and in Silk Fibroin Membrane

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